dsRNA For Treating Viral Infection

ABSTRACT

The invention relates to double-stranded ribonucleic acids (dsRNAs) targeting gene expression of phosphatidylinositol 4-kinase (PI4K), in particular human phosphatidylinositol 4-kinase, catalytic, beta polypeptide (PIK4CB) or human phosphatidylinositol 4-kinase, catalytic, alpha polypeptide (PIK4CA), and their use for treating infection by positive stranded RNA viruses such as hepatitis C virus (HCV). Each dsRNA comprises an antisense strand having a nucleotide sequence which is less that 30 nucleotides in length, generally 19-25 nucleotides in length, and which is substantially complementary to at least a part of the PIK4CB or PIK4CA target mRNA. A plurality of such dsRNA may be employed to provide therapeutic benefit. The invention also relates to a pharmaceutical composition comprising the dsRNA together with a pharmaceutically acceptable carrier, and including a delivery modality such as fully encapsulated liposomes or lipid complexes. The invention further includes methods for treating diseases caused by positive stranded RNA virus infection using the pharmaceutical compositions; and methods for inhibiting the propogation of positive stranded RNA viruses in and between cells.

FIELD OF THE INVENTION

This invention relates to double-stranded ribonucleic acid (dsRNA)targeting human phosphatidylinositol 4-kinase, in particular humanphosphatidylinositol 4-kinase catalytic, beta polypeptide (PIK4CB;NM_(—)002651) and/or human phosphatidylinositol 4-kinase alphapolypeptide (PIK4CA; NM_(—)002650) and its use (via RNA interference) totreat pathological processes mediated by infection from positivestranded RNA viruses such as hepatitis C virus (HCV).

BACKGROUND OF THE INVENTION

RNA-dependent RNA polymerase positive strand RNA viruses make up a largesuperfamily of viruses from many distinct subfamilies. These virusesspan both the plant and animal kingdoms causing pathologies ranging frommild phenotypes to severe debilitating disease. The composition of thepositive strand RNA virus polymerase supergroup is as follows. I.Picorna- (HAV, polio, Coxsackie), noda-, como-, nepo-, poty-, bymo-,sobemoviruses, and luteoviruses (yellows, yellow drawf, and leafrollvirus). II. Carmo-, tombus-, dianthoviruses, pestiviruses, toga-, echo-,Dengue, hepatitis C virus, flaviviruses. III. Tobamo-, tobra-, hordei-,tricoma-, alpha, rubi-, furoviruses, hepatitis E virus, potex-, carla-,tymoviruses, and apple chlorotic leaf spot virus. The genomes ofpositive-strand RNA viruses encode RNA-dependent RNA polymerases whichis the only viral protein containing motifs conserved across this classof viruses. This conservation is significant since this class of virusescontains significant phylogenetic variability, one would predict thereare many ways in which the viruses infect cells and maintain stablereplication. Besides the many differences, all the viruses in this classdepend on a single fundamental step of RNA dependent positive strand RNAtranscription. Since this step is essential for the viral life cyclethis virus uses many host proteins to start and maintain RNA dependentRNA polymerase activity. Without the interaction of host factors theviruses would be unable to survive. Therefore a possible therapeuticintervention for inhibiting viral infection would be blocking the virushost interaction. If host factors essential for the virus but notessential for the host can be manipulated, then the ability to blockviral infection could be achieved. Targeting host proteins has alreadybeen proven to be an efficacious approach to disrupt viral infection andreplication for HIV, HCV, small pox, etc.

The significance of positive strand RNA viruses is the impact on humanhealth and viability. Several positive strand RNA viruses infect humansand in many cases lead to debilitating disease and/or morbidity. Severalviruses with a particular burden on human health is the Dengue virus(hemoragic fever), HCV (chronic liver disease, liver failure, fibrosis,and cancer), and HEV (fulminant hepatic failure). The liver and blooddiseases caused by these viruses causes millions of deaths world wideand costs the heath care industry billions of dollars in liver relatedillness. The significance of finding therapies for curbing viralinfection is great and would improve human health around the world.

As such there exists an unmet need for effective treatment of infectionscaused by HCV and other positive strand RNA viruses (listed above).

This specification also relates to double-stranded RNA molecules(dsRNA). dsRNA have been shown to block gene expression in a highlyconserved regulatory mechanism known as RNA interference (RNAi). WO99/32619 (Fire et al.) discloses the use of a dsRNA of at least 25nucleotides in length to inhibit the expression of genes in C. elegans.dsRNA has also been shown to degrade target RNA in other organisms,including plants (see, e.g., WO 99/53050, Waterhouse et al.; and WO99/61631, Heifetz et al.), Drosophila (see, e.g., Yang, D., et al.,Curr. Biol. (2000) 10:1191-1200), and mammals (see WO 00/44895, Limmer;and DE 101 00 586.5, Kreutzer et al.). This natural mechanism has nowbecome the focus for the development of a new class of pharmaceuticalagents for treating disorders that are caused by the aberrant orunwanted regulation of a gene.

PCT Publications WO 2003016572, WO 2003070750 and WO 2005028650 discloseprevious efforts to develop nucleic acid based RNAi medicaments for thetreatment of disease caused by HCV infection. PCT PublicationWO2006074346 discloses previous efforts to treat RSV infection usingRNAi medicaments.

Despite significant advances in the field of RNAi and advances in thetreatment of pathological processes mediated by viral infection, thereremains a need for agents that can inhibit the progression of viralinfection and that can treat diseases associated with viral infection.The instant invention discloses compounds, compositions and methods thatmeet this need, and provide other benefits as well.

SUMMARY OF THE INVENTION

The invention provides compositions and methods for treating infectionby positive stranded RNA viruses (such as HCV, HPV, Dengue and polio),by reducing the level or activity of the human host factorphosphatidylinositol 4-kinase, catalytic, beta polypeptide (PIK4CB;NM_(—)002651), and/or phosphatidylinositol 4-kinase, catalytic, alphapolypeptide (PIK4CA; NM_(—)002650) in cells where such viruses wouldreplicate, such as the liver.

It is disclosed herein that proliferation of positive stranded RNAviruses can be inhibited by using double-stranded ribonucleic acid(dsRNA) to silence expression of the human host cell gene PIK4CB, and/orPIK4CA required for their proliferation.

The invention provides multiple embodiments, including in particular:

A double-stranded ribonucleic acid (dsRNA) for inhibiting the expressionof phosphatidylinositol 4-kinase (PI4K) level or activity in a cell,wherein said dsRNA comprises at least two sequences that arecomplementary to each other and wherein a sense strand comprises a firstsequence and an antisense strand comprises a second sequence comprisinga region of complementarity which is substantially complementary to atleast a part of a mRNA encoding PI4K, and wherein said region ofcomplementarity is less than 30 nucleotides in length and wherein saiddsRNA, upon contact with a cell expressing said PI4K gene, inhibitsexpression of said PIK4 gene. Such dsRNA may have chemicalmodifications, and may be conjugated to other moieties. In addition,such dsRNA may be provided in a pharmaceutical composition.

An embodied method is a method for inhibiting the expression of thephosphatidylinositol 4-kinase, catalytic, beta polypeptide (PIK4CB) geneor the phosphatidylinositol 4-kinase, catalytic, beta polypeptide(PIK4CA) gene in a cell, the method comprising:

(a) introducing into the cell a double-stranded ribonucleic acid(dsRNA), wherein the dsRNA comprises at least two sequences that arecomplementary to each other and wherein a sense strand comprises a firstsequence and an antisense strand comprises a second sequence comprisinga region of complementarity which is substantially complementary to atleast a part of a mRNA encoding PIK4CB or PIK4CA, and wherein saidregion of complementarity is less than 30 nucleotides in length; and

(b) maintaining the cell produced in step (a) for a time sufficient toobtain degradation of the mRNA transcript of the PIK4CB gene (or PIK4CA,as selected), thereby inhibiting expression or activity of PIK4CB (orPIK4CA, as selected) in the cell.

Alternatively, the invention embodies a method of treating apathological processes mediated by positive stranded RNA virus infectioncomprising administering to a patient in need of such treatment, a dsRNAof the invention. The positive stranded RNA virus may be selected fromamong hepatitis C virus (HCV), human papilloma virus (HPV), and Denguevirus.

Alternative embodiments include a vector for inhibiting the expressionof PIK4CB or PIK4CA in a cell; and cells comprising such vectors.

An alternative embodiment includes a method of treating an HCV infectioncomprising administering to a patient in need of such treatment atherapeutically effective amount of a pharmaceutical compositioncomprising a dsRNA of the invention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1. Structure of the HCV constructs. A. The complete HCV genome. B.The subgenomic HCV replicon, used for the Clone A (subgenomic replicon)cells. The structural proteins are replaced with a neomycin resistancegene and a firefly luciferase reporter downstream of the 5′ UTR. C. Thereporter construct with the HCV proteins removed, used for the Clone Ar(cells lacking the subgenomic replicon) cells.

FIG. 2. Phenotype validation of siRNA hits. Hits from the large scalekinome siRNA screen re-analyzed. A. Results of testing dsRNA asindividual duplexes PIK4CA1-PIK4CA4 (column 1-4) as a PIK4CA Smart Pool(col. 5), as individual duplexes PIK4CB1-PIK4CB4 (col. 6-9) or as aPIK4CB Smart Pool (Col. 10). Results are measured relative to GAPDH(control; column 11), Assay performed using 25 nM of dsRNA per wellusing Clone A cells; Bright-Glo activity measured at 72 hours posttransfection. dsRNA targeting GAPDH (column 11) was used as the negativecontrol and dsRNA targeting pGL2 (column 12) was the positive control.

FIG. 3. RTPCR of PIK4CA and PIK4CB. Huh7 replicon cells were transfectedwith siRNA for 72 hours, mRNA was isolated and RTPCR was analyzed byTaqman. Results were normalized to GAPDH transfected cells. A.Transfection of PIK4CA siRNAs, Taq man RTPCR using PIK4CA primers. B.Transfection of PIK4CA siRNAs, Taq man RTPCR using PIK4CB primers. C.Transfection of PIK4CB siRNAs, Taq man RTPCR using PIK4CB primers. D.Transfection of PIK4CB siRNAs, Taq man RTPCR using PIK4CA primers.GOI=Gene-of-Interest. PIK4CAsp=PIK4CA Smart Pool; PIK4CBsp=PIK4CB SmartPool.

FIG. 4. A) mRNA expression of PIK4CA (light bars) or PIK4CB (dark bars)after treatment by the indicated siRNA targeting PIK4CA (25 nM). B) mRNAexpression of PIK4CA (light bars) or PIK4CB (dark bars) after treatmentby the indicated siRNA targeting PIK4CB (25 nM).

FIG. 5. Western blot results demonstrating level of protein expressionof PI4KB, NS3 or actin (as indicated) after treatment of PI4KA siRNA(col 1-col 3 correspond to Table 2; PI4KA1; PIK4A2 and PIK4A3,respectively); or PI4KB siRNA (col 4-col 6 correspond to Table 1;PI4KB1; PIK4B2 and PIK4B3, respectively). GAPDH siRNA treatment is shownas a control.

FIG. 6. shRNA sequences targeting PIK4CA and PIK4CB. A) Results oftreatment of Clone A cells with indicated shRNA construct. Light barsindicate luciferase activity; dark bars indicate cell viability. Allresults are compared to control GAPDH treated cells: B) Effect oftreatment with indicated shRNA on PI4KA expression (GFP normalized); C)Effect of treatment with indicated shRNA on PI4KB expression (GFPnormalized); D) Western blot results demonstrating level of proteinexpression of PI4KB, NS3 or actin (as indicated) after treatment withshRNA targeting PI4KA (col 1-col 5 correspond to shA1-shA5,respectively); or shRNA targeting PI4KB (col 6-col 10 correspond toshB1-shB5, respectively). GFP shRNA treatment is shown as a control, allresults taken at 96 hours after treatment with indicated shRNA; E)Western blot measuring effect of shA2 and shB1 on protein expression, 3weeks after shRNA transduction (GFP control).

FIG. 7. Inhibition of HCV replication (live virus). Dose dependence ofHCV replication upon treatment by the indicated siRNA. Cells are treatedbefore HCV infection with indicated siRNA against either PIK4CA orPIK4CB. A) 25 nM (grey bar); 1.5 nM (white bar); 0.1 nM (dark bar).Results are normalized to HCV replication upon GAPDH siRNA treatment.Renilla siRNA is positive control. B) Expression of target mRNA ininfected cells.

FIG. 8. Inhibition of HCV replication (live virus). Dose dependence ofHCV replication upon treatment by the indicated siRNA. Cells are treatedafter HCV infection with indicated siRNA against either PIK4CA orPIK4CB. A) Effect on viral replication 24 hours after treatment withindicated siRNA (25 nM). Dark bars—viral luciferase (activity); Lightbars—cell viability. Results are normalized to HCV replication uponGAPDH siRNA treatment. Renilla siRNA is positive control. B) Timedependence of HCV replication after treatment with indicated siRNA. Dark(first) bar—24 h; light (second) bar—48 h; white (third) bar—72 h; grey(fourth) bar—96 h.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a solution to the problem of treating diseasesassociated with infection by positive stranded RNA viruses (such as HCV,HPV, Dengue and polio), by reducing the level of the human host factorphosphatidylinositol 4-kinase, catalytic, beta polypeptide (PIK4CB;NM_(—)002651), and/or phosphatidylinositol 4-kinase, catalytic, alphapolypeptide (PIK4CA; NM_(—)002650) in cells where such viruses wouldreplicate. It is disclosed herein that proliferation of positivestranded RNA viruses can be inhibited by using double-strandedribonucleic acid (dsRNA) to silence expression of the human host cellgene PIK4CB, and/or PIK4CA required for their proliferation.

In addition, it is disclosed herein for the first time that selectedchemical modifications of these dsRNA are highly preferred embodimentswhich provide surprisingly reduced toxicity, reduced immunogenicity,improved pharmacological behaviour and other benefits.

The invention provides double-stranded ribonucleic acid (dsRNA), as wellas compositions, pharmaceutical compositions and methods for inhibitingthe propagation of positive stranded RNA viruses in a cell or mammalusing the dsRNA. The invention also provides compositions and methodsfor treating pathological conditions and diseases in a mammal caused byinfection from positive strand RNA viruses using dsRNA.

The dsRNA of the invention comprises an RNA strand (the antisensestrand) having a region which is less than 30 nucleotides in length,generally 19-24 nucleotides in length, and is substantiallycomplementary to at least part of the gene product (pre-mRNA or maturemRNA) transcript of human phosphatidylinositol 4-kinase, catalytic, betasubunit polypeptide (PIK4CB; NM_(—)002651, and/or humanphosphatidylinositol 4-kinase, catalytic, alpha polypeptide PIK4CA;NM_(—)002650). The use of these dsRNAs enables the targeted degradationor inactivation of mRNAs of genes that are implicated in replication andor maintenance of positive stranded RNA infection in mammals. Usingcell-based and animal assays, the present inventors have demonstratedthat very low dosages of these dsRNA can specifically and efficientlymediate RNAi, resulting in significant inhibition of replication andinfection. Thus, the methods and compositions of the inventioncomprising these dsRNAs are useful for treating pathological processesmediated by positive strand RNA virus infection.

Human phosphatidylinositol 4-kinase, catalytic, beta subunit polypeptide(PIK4CB; NM_(—)002651; also sometimes called PI4KB; PIK4B; pi4K92; PI4Kbeta; PI4K-BETA; PI4KIIIbeta), and human phosphatidylinositol 4-kinase,catalytic, alpha polypeptide (PIK4CA; NM_(—)002650; also sometimescalled PI4KA; PIK4A; pi4K230; FLJ16556; and PI4K-ALPHA) arephosphatidylinositol 4-kinases. Phosphatidylinositol 4-kinase is knownalternatively as PI4K, PI 4-kinase or PIK4 in the literature. Thisspecification uses such terms interchangeably unless context indicates aspecific selection. There are four PI4K enzymes in mammalian cells whichfall into two classes. The first is the type III PI4Ks, including PIK4CAand PIK4CB, conserved from yeast to man. The yeast orthologues Stt4p andPik1p respectively are both essential genes with non-overlappingfunction. The type II PI4Ks, PI4KIIα and PI4KIIβ, distinct from theclass III enzymes, also have a yeast homologue, LSB6, which is anonessential gene. PIK4CB is the best characterized mammalian gene whichis localized to the Golgi, functions in a complex with the small GTPaseADP-ribosylation factor (ARF), and is thought to regulate Golgi toplasma membrane secretion. The class II α and β enzymes have also beenshown to be involved in Golgi/trans-Golgi trafficking. The class III αisoform seems to play a role at the plasma membrane and ER but not theGolgi.

In addition to the subcellular localization of the PI4Ks is the uniquefunctions of the enzymes at the respective compartment. PIK4CB isinvolved in production of PtdIns4P and PtdIns-4,5P2 pools, the regulatedtransport of ceramide from the ER to the Golgi, which leads tospingomyelin synthesis, and is involved in the structural integrity ofthe Golgi by maintaining the PI(4)P-rich domains that allow the dockingof AP-1 machinery. Disruption of PIK4CB causes changes in the structureof the Golgi complex, causes secretory defects in polarized cells, andinhibits protein transport to the plasma membrane.

The class II and III PI4K α and β enzymes generate PtdIns 4-phosphate,the precursor of several regulatory phosphoinositides. Thesephosphoinositides control various cellular signalling and traffickingprocesses by recruiting regulatory proteins into organized signallingcomplexes. The production of PtdIns 4-phosphate [PtdIns4P] from PtdIns,the first step in the formation of PtdIns(4,5)P2 and PtdIns(3,4,5)P3.PtdIns(4,5)P2 is the main substrate of the phospholipase C (PLC)enzymes, yielding inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] anddiacylglycerol (DAG) involved in Ca²⁺ signaling. PtdIns(4,5)P2 alsocontrols several types of ion channel and enzymes, such as phospholipaseD (PLD), and interacts with proteins that link membranes to the actincytoskeleton 3 and 5. PtdIns(3,4,5)P3, generated from PtdIns(4,5)P2 bythe class I PtdIns 3-kinases, regulates a range of processes, such ascell metabolism and the antiapoptotic pathway via the serine/threoninekinase Akt but also controls tyrosine kinases, such as Btk and guanineexchange factors for small GTP-binding proteins. The production of thesesignaling phosphoinositides relies upon both the activity of theirsynthesizing enzymes and their precursor supply, thus PtdIns 4-kinaseshave a role in cellular regulation.

The positive strand RNA viruses of which are dependent on human PIK4CBor PIK4CA for replication are believed to include: I. Picorna- (HAV,polio, Coxsackie), noda-, como-, nepo-, poty-, bymo-, sobemoviruses, andluteoviruses (yellows, yellow drawf, and leafroll virus). II. Carmo-,tombus-, dianthoviruses, pestiviruses, toga-, echo-, Dengue, hepatitis Cvirus, flaviviruses. III. Tobamo-, tobra-, hordei-, tricoma-, alpha,rubi-, furoviruses, hepatitis E virus, potex-, carla-, tymoviruses, andapple chlorotic leaf spot virus.

The following detailed description discloses how to make and use thedsRNA and compositions containing dsRNA to inhibit the expression ofpositive-strand RNA viruses, as well as compositions and methods fortreating diseases and disorders caused by positive-strand RNA virusinfection, e.g. liver disease, liver failure, fibrosis, cancer, lungdisease and its complications (described further below). Thepharmaceutical compositions of the invention comprise a dsRNA having anantisense strand comprising a region of complementarity which is lessthan 30 nucleotides in length, generally 19-24 nucleotides in length,and is substantially complementary to at least part of an RNA transcriptof PIK4CB and/or PIK4CA together with a pharmaceutically acceptablecarrier. An embodiment of the invention is the employment of more thanone dsRNA, optionally targeting different segments of the PIK4CB, and/orPIK4CA RNA transcript, in combination, in a pharmaceutical formulation.

Accordingly, certain aspects of the invention provide pharmaceuticalcompositions comprising the dsRNA of the invention together with apharmaceutically acceptable carrier, methods of using the compositionsto inhibit expression of PIK4CB, and/or PIK4CA and methods of using thepharmaceutical compositions to treat diseases caused by positive-strandRNA virus infection.

DEFINITIONS

For convenience, the meaning of certain terms and phrases used in thespecification, examples, and appended claims, are provided below. Ifthere is an apparent discrepancy between the usage of a term in otherparts of this specification and its definition provided in this section,the definition in this section shall prevail.

“G,” “C,” “A” and “U” each generally stand for a nucleotide thatcontains guanine, cytosine, adenine, and uracil as a base, respectively.However, it will be understood that the term “ribonucleotide” or“nucleotide” can also refer to a modified nucleotide, as furtherdetailed below, or a surrogate replacement moiety. The skilled person iswell aware that guanine, cytosine, adenine, and uracil may be replacedby other moieties without substantially altering the base pairingproperties of an oligonucleotide comprising a nucleotide bearing suchreplacement moiety. For example, without limitation, a nucleotidecomprising inosine as its base may base pair with nucleotides containingadenine, cytosine, or uracil. Hence, nucleotides containing uracil,guanine, or adenine may be replaced in the nucleotide sequences of theinvention by a nucleotide containing, for example, inosine. Sequencescomprising such replacement moieties are embodiments of the invention.

As used herein, “target sequence” refers to a contiguous portion of thenucleotide sequence of an mRNA molecule formed during the transcriptionof PIK4CB, including mRNA that is a product of RNA processing of aprimary transcription product.

As used herein, the term “strand comprising a sequence” refers to anoligonucleotide comprising a chain of nucleotides that is described bythe sequence referred to using the standard nucleotide nomenclature.

As used herein, and unless otherwise indicated, the term“complementary,” when used to describe a first nucleotide sequence inrelation to a second nucleotide sequence, refers to the ability of anoligonucleotide or polynucleotide comprising the first nucleotidesequence to hybridize and form a duplex structure under certainconditions with an oligonucleotide or polynucleotide comprising thesecond nucleotide sequence, as will be understood by the skilled person.Such conditions can, for example, be stringent conditions, wherestringent conditions may include: 400 mM NaCl, 40 mM PIPES pH 6.4, 1 mMEDTA, 50° C. or 70° C. for 12-16 hours followed by washing. Otherconditions, such as physiologically relevant conditions as may beencountered inside an organism, can apply. The skilled person will beable to determine the set of conditions most appropriate for a test ofcomplementarity of two sequences in accordance with the ultimateapplication of the hybridized nucleotides.

This includes base-pairing of the oligonucleotide or polynucleotidecomprising the first nucleotide sequence to the oligonucleotide orpolynucleotide comprising the second nucleotide sequence over the entirelength of the first and second nucleotide sequence. Such sequences canbe referred to as “fully complementary” with respect to each otherherein. However, where a first sequence is referred to as “substantiallycomplementary” with respect to a second sequence herein, the twosequences can be fully complementary, or they may form one or more, butgenerally not more than 4, 3 or 2 mismatched base pairs uponhybridization, while retaining the ability to hybridize under theconditions most relevant to their ultimate application. However, wheretwo oligonucleotides are designed to form, upon hybridization, one ormore single stranded overhangs, such overhangs shall not be regarded asmismatches with regard to the determination of complementarity. Forexample, a dsRNA comprising one oligonucleotide 21 nucleotides in lengthand another oligonucleotide 23 nucleotides in length, wherein the longeroligonucleotide comprises a sequence of 21 nucleotides that is fullycomplementary to the shorter oligonucleotide, may yet be referred to as“fully complementary” for the purposes of the invention.

“Complementary” sequences, as used herein, may also include, or beformed entirely from, non-Watson-Crick base pairs and/or base pairsformed from non-natural and modified nucleotides, in as far as the aboverequirements with respect to their ability to hybridize are fulfilled.

The terms “complementary”, “fully complementary” and “substantiallycomplementary” herein may be used with respect to the base matchingbetween the sense strand and the antisense strand of a dsRNA, or betweenthe antisense strand of a dsRNA and a target sequence, as will beunderstood from the context of their use.

As used herein, a polynucleotide which is “substantially complementaryto at least part of” a messenger RNA (mRNA) refers to a polynucleotidewhich is substantially complementary to a contiguous portion of the mRNAof interest (e.g., PIK4CB or PIK4CA). For example, a polynucleotide iscomplementary to at least a part of PIK4CB mRNA if the sequence issubstantially complementary to a non-interrupted portion of an mRNAencoding PIK4CB. Similarly a polynucleotide is complementary to at leasta part of PIK4CA mRNA if the sequence is substantially complementary toa non-interrupted portion of an mRNA encoding PIK4CA.

The term “double-stranded RNA” or “dsRNA”, as used herein, refers to acomplex of ribonucleic acid molecules, having a duplex structurecomprising two anti-parallel and substantially complementary, as definedabove, nucleic acid strands. The two strands forming the duplexstructure may be different portions of one larger RNA molecule, or theymay be separate RNA molecules. Where separate RNA molecules, such dsRNAare often referred to in the literature as siRNA (“short interferingRNA”). Where the two strands are part of one larger molecule, andtherefore are connected by an uninterrupted chain of nucleotides betweenthe 3′-end of one strand and the 5′ end of the respective other strandforming the duplex structure, the connecting RNA chain is referred to asa “hairpin loop”, “short hairpin RNA” or “shRNA”. Where the two strandsare connected covalently by means other than an uninterrupted chain ofnucleotides between the 3′-end of one strand and the 5′ end of therespective other strand forming the duplex structure, the connectingstructure is referred to as a “linker”. The RNA strands may have thesame or a different number of nucleotides. The maximum number of basepairs is the number of nucleotides in the shortest strand of the dsRNAminus any overhangs that are present in the duplex. In addition to theduplex structure, a dsRNA may comprise one or more nucleotide overhangs.In addition, as used in this specification, “dsRNA” may include chemicalmodifications to ribonucleotides, internucleoside linkages, end-groups,caps, and conjugated moieties, including substantial modifications atmultiple nucleotides and including all types of modifications disclosedherein or known in the art. Any such modifications, as used in an siRNAtype molecule, are encompassed by “dsRNA” for the purposes of thisspecification and claims.

As used herein, a “nucleotide overhang” refers to the unpairednucleotide or nucleotides that protrude from the duplex structure of adsRNA when a 3′-end of one strand of the dsRNA extends beyond the 5′-endof the other strand, or vice versa. “Blunt” or “blunt end” means thatthere are no unpaired nucleotides at that end of the dsRNA, i.e., nonucleotide overhang. A “blunt ended” dsRNA is a dsRNA that isdouble-stranded over its entire length, i.e., no nucleotide overhang ateither end of the molecule. For clarity, chemical caps or non-nucleotidechemical moieties conjugated to the 3′ end or 5′ end of an siRNA are notconsidered in determining whether an siRNA has an overhang or is bluntended.

The term “antisense strand” refers to the strand of a dsRNA whichincludes a region that is substantially complementary to a targetsequence. This strand is also known as the “guide” sequence, and is usedin the functioning RISC complex to guide the complex to the correct mRNAfor cleavage. As used herein, the term “region of complementarity”refers to the region on the antisense strand that is substantiallycomplementary to a sequence, for example a target sequence, as definedherein. Where the region of complementarity is not fully complementaryto the target sequence, the mismatches are most tolerated in theterminal regions and, if present, are generally in a terminal region orregions, e.g., within 6, 5, 4, 3, or 2 nucleotides of the 5′ and/or 3′terminus. This use of “antisense”, because it relates to an RNAcompound, is different from antisense DNA compounds, which are adifferent though related field of nucleic acid therapeutic.

The term “sense strand,” as used herein, refers to the strand of a dsRNAthat includes a region that is substantially complementary to a regionof the antisense strand. This strand is also known as the “anti-guide”sequence because it contains the same sequence of nucleotides as thetarget sequence and therefore binds specifically to the guide sequence.

“Introducing into a cell”, when referring to a dsRNA, means facilitatinguptake or absorption into the cell, as is understood by those skilled inthe art. Absorption or uptake of dsRNA can occur through unaideddiffusive or active cellular processes, or by auxiliary agents ordevices. The meaning of this term is not limited to cells in vitro; adsRNA may also be “introduced into a cell”, wherein the cell is part ofa living organism. In such instance, introduction into the cell willinclude the delivery to the organism. For example, for in vivo delivery,dsRNA can be injected into a tissue site or administered systemically.In vitro introduction into a cell includes methods known in the art suchas electroporation and lipofection.

The terms “silence” and “inhibit the expression of”, in as far as theyrefer to PIK4CB or PIK4CA, herein refer to the at least partialsuppression of the expression of PIK4CB or PIK4CA in a cell treated withdsRNA targeting PIK4CB or PIK4CA, as manifested by a reduction of theamount of mRNA transcribed or available compared to normal (untreated)cells. This measurement may be determined by comparing mRNA levels intreated cells (which may be isolated from a first cell or group of cellswhich have been treated such that the expression of PIK4CB or PIK4CA isinhibited), as compared to a second cell or group of cells substantiallyidentical to the first cell or group of cells but which has or have notbeen so treated (control cells). The degree of inhibition is usuallyexpressed in terms of

${\frac{\left( {{mRNA}\mspace{14mu} {in}\mspace{14mu} {control}\mspace{14mu} {cells}} \right) - \left( {{mRNA}\mspace{14mu} {in}\mspace{14mu} {treated}\mspace{14mu} {cells}} \right)}{\left( {{mRNA}\mspace{14mu} {in}\mspace{14mu} {control}\mspace{14mu} {cells}} \right)} \cdot 100}\%$

Alternatively, the degree of inhibition may be given in terms of areduction of a parameter that is functionally linked to genetranscription, e.g. the amount of polypeptide, or the number of cellsdisplaying a certain phenotype, e.g kinase activity specificallyassociated with PIK4CB or PIK4CA, or susceptibility to infection. Inprinciple, gene silencing may be determined in any cell expressing thegene of interest, either constitutively or by genetic engineering, andby any appropriate assay. However, when a reference is needed in orderto determine whether a given dsRNA inhibits the expression of the PIK4CBor PIK4CA by a certain degree and therefore is encompassed by theinstant invention, the assay provided in the Examples below shall serveas such reference.

For example, in certain instances, expression of the PIK4CB or PIK4CAgene is inhibited, when it is suppressed by at least about 20%, 25%,35%, or 50% by administration of the double-stranded RNA of theinvention. In some embodiments, the PIK4CB or PIK4CA gene is suppressedby at least about 60%, 70%, or 80% by administration of thedouble-stranded oligonucleotide of the invention. In some embodiments,the PIK4CB or PIK4CA gene is suppressed by at least about 85%, 90%, or95% by administration of the double-stranded oligonucleotide of theinvention. The results in FIG. 2 demonstrate that each tested dsRNAtargeted to PIK4CB (or PIK4CA) is effective to reduce the relative levelof expression product in the HCV replicon assay from 10% to 90%. Theresults in FIG. 3 demonstrate that each tested dsRNA targeted to PIK4CB(or PIK4CA) is effective to reduce the level of PIK4CB (or PIK4CA) mRNAlevels in a cell from 10% to 90%.

As used herein in the context of positive-strand RNA virus infection,the terms “treat”, “treatment”, and the like, refer to relief from oralleviation of pathological processes mediated by positive-strand RNAvirus infection. Such description includes use of the therapeutic agentsof the invention for prophylaxis or prevention of positive-strand RNAvirus infection, and relief from symptoms or pathologies caused bypositive-strand RNA virus infection. In the context of the presentinvention insofar as it relates to any of the other conditions recitedherein below (other than pathological processes mediated bypositive-strand RNA virus infection), the terms “treat”, “treatment”,and the like mean to relieve or alleviate at least one symptomassociated with such condition, or to slow or reverse the progression ofsuch condition.

As used herein, the phrases “therapeutically effective amount” and“prophylactically effective amount” refer to an amount that provides atherapeutic benefit in the treatment, prevention, or management ofpathological processes mediated by positive-strand RNA virus infectionor an overt symptom of pathological processes mediated bypositive-strand RNA virus infection. The specific amount that istherapeutically effective can be readily determined by ordinary medicalpractitioner, and may vary depending on factors known in the art, suchas, e.g. the type of pathological processes mediated by positive-strandRNA virus infection, the patient's history and age, the stage ofpathological processes mediated by positive-strand RNA virus infection,and the administration of other anti-pathological agents.

As used herein, a “pharmaceutical composition” comprises apharmacologically effective amount of a dsRNA and a pharmaceuticallyacceptable carrier. As used herein, “pharmacologically effectiveamount,” “therapeutically effective amount” or simply “effective amount”refers to that amount of a dsRNA effective to produce the intendedpharmacological, therapeutic or preventive result. For example, if agiven clinical treatment is considered effective when there is at leasta 25% reduction in a measurable parameter associated with a disease ordisorder, a therapeutically effective amount of a drug for the treatmentof that disease or disorder is the amount necessary to effect at least a25% reduction in that parameter.

The term “pharmaceutically acceptable carrier” refers to a carrier foradministration of a therapeutic agent. Such carriers include, but arenot limited to, saline, buffered saline, dextrose, water, glycerol,ethanol, and combinations thereof. The term specifically excludes cellculture medium. For drugs administered orally, pharmaceuticallyacceptable carriers include, but are not limited to pharmaceuticallyacceptable excipients such as inert diluents, disintegrating agents,binding agents, lubricating agents, sweetening agents, flavoring agents,coloring agents and preservatives. Suitable inert diluents includesodium and calcium carbonate, sodium and calcium phosphate, and lactose,while corn starch and alginic acid are suitable disintegrating agents.Binding agents may include starch and gelatin, while the lubricatingagent, if present, will generally be magnesium stearate, stearic acid ortalc. If desired, the tablets may be coated with a material such asglyceryl monostearate or glyceryl distearate, to delay absorption in thegastrointestinal tract.

As used herein, a “transformed cell” is a cell into which a vector hasbeen introduced from which a dsRNA molecule may be expressed.

Double-Stranded Ribonucleic Acid (dsRNA)

In one embodiment, the invention provides double-stranded ribonucleicacid (dsRNA) molecules for inhibiting the expression of PIK4CB and/orPIK4CA, and thereby inhibiting positive-strand RNA virus replication orpropagation, in a cell or mammal, wherein the dsRNA comprises anantisense strand comprising a region of complementarity which iscomplementary to at least a part of an mRNA formed in the expression ofPIK4CB or PIK4CA, and wherein the region of complementarity is less than30 nucleotides in length, generally 19-24 nucleotides in length, andwherein said dsRNA, upon contact with a cell expressing said PIK4CB orPIK4CA gene, inhibits the expression of said PIK4CB or PIK4CA gene by atleast 10%, 25%, or 40%.

The dsRNA comprises two RNA strands that are sufficiently complementaryto hybridize to form a duplex structure. One strand of the dsRNA (theantisense strand) comprises a region of complementarity that issubstantially complementary, and generally fully complementary, to atarget sequence, derived from the sequence of gene product of the PIK4CBor PIK4CA gene, the other strand (the sense strand) comprises a regionwhich is complementary to the antisense strand, such that the twostrands hybridize and form a duplex structure when combined undersuitable conditions. Generally, the duplex structure is between 15 and30, more generally between 18 and 25, yet more generally between 19 and24, and most generally between 19 and 21 base pairs in length.Similarly, the region of complementarity to the target sequence isbetween 15 and 30, more generally between 18 and 25, yet more generallybetween 19 and 24, and most generally between 19 and 21 nucleotides inlength. The dsRNA of the invention may be blunt ended (e.g. where eachnucleotide on either strand has a nucleotide suitable for base-pairingon the other strand), or it may further comprise one or moresingle-stranded nucleotide overhang(s), commonly on the 3′ end. ThedsRNA can be synthesized by standard methods known in the art as furtherdiscussed below, e.g., by use of an automated DNA synthesizer, such asare commercially available from, for example, Biosearch, AppliedBiosystems, Inc.

In specific embodiments, the dsRNA comprises, for targeting PIK4CB, astrand selected from the sense sequences of Table 1 and a secondsequence selected from the group consisting of the antisense sequencesof Table 1. Alternative agents that target elsewhere in the PIK4CBtarget sequence, e.g. slightly upstream or downstream from the agentsidentified in Table 1, can readily be determined using the sequencelisted in Table 1, and the flanking mRNA or genomic sequence found atNCBI Accession No.: NM_(—)002651.

In specific embodiments, the dsRNA comprises, for targeting PIK4CA, astrand selected from the sense sequences of Table 2 and a secondsequence selected from the group consisting of the antisense sequencesof Table 2. Alternative agents that target elsewhere in the PIK4CAtarget sequence, e.g. slightly upstream or downstream from the agentsidentified in Table 2, can readily be determined using the sequencelisted in Table 2, and the flanking mRNA or genomic sequence found atNCBI Accession No.: NM_(—)002650.

In further embodiments, the dsRNA comprises at least one duplex sequenceselected from the duplex sequences provided in Table 1 or from Table 2.In other embodiments, the therapeutic agent may comprise two or moreduplex sequences selected from Table 1 and/or from Table 2. Generally,each dsRNA comprises two oligonucleotide strands, wherein oneoligonucleotide is described as the sense strand in the Table and thesecond oligonucleotide is described as the antisense strand in the sameTable. Each Table provides a duplex name for each preferred dsRNA.Nucleotide bases are indicated using standard nucleotide notation.

TABLE 1  Duplex siRNA (dsRNA) targeting PIK4CB Duplex Antisense SequenceSEQ ID SEQ ID Name (Guide Sequence) No.: Sense Sequence No.: PIK4CB1GGACGUGGGUGAUGCCAUUUUTT 1 AAAAUGGCAUCACCCACGUCCTT 105 PIK4CB2GGGAUGACCUUCGGCAAGAUUTT 2 AAUCUUGCCGAAGGUCAUCCCTT 106 PIK4CB3GAGAUCCGUUGCCUAGAUGUUTT 3 AACAUCUAGGCAACGGAUCUCTT 107 PIK4CB4GCACCGAGAGUAUUGAUAAUUTT 4 AAUUAUCAAUACUCUCGGUGCTT 108 PIK4CB5SMARTpool PIKC4B1-B4 PIK4CB1-B4 PIK4CB6 UUAUCAAUACUCUCGGUGCTGTT 5GCACCGAGAGUAUUGAUAATT 109 PIK4CB7 UUGUACUCCAGGCUCCUUGGATT 6CAAGGAGCCUGGAGUACAATT 110 PIK4CB8 UUGGACACUGAGGCAUCCGTTTT 7CGGAUGCCUCAGUGUCCAATT 111 PIK4CB9 UAGUCAACCAAGUGUAAUCTGTT 8GAUUACACUUGGUUGACUATT 112 PIK4CB10 UUGGGCACAGUGCUGAAGCTGTT 9GCUUCAGCACUGUGCCCAATT 113 PIK4CB11 AUGGGUAAUACCACAUUCGGGTT 10CGAAUGUGGUAUUACCCAUTT 114 PIK4CB12 AAUCAUGCCACUAUCAGCCGATT 11GGCUGAUAGUGGCAUGAUUTT 115 PIK4CB13 UCUCGUUUGAAGGCUGUCGGGTT 12CGACAGCCUUCAAACGAGATT 116 PIK4CB14 UACCACAUGAUCCUUCGUGTTTT 13CACGAAGGAUCAUGUGGUATT 117 PIK4CB15 UAAUGCUCUGGCGGCAACGGTTT 14CGUUGCCGCCAGAGCAUUATT 118 PIK4CB16 AUCUUGUAUGGCUUGAUCCAATT 15GGAUCAAGCCAUACAAGAUTT 119 PIK4CB17 AUCACAUCCACAAACUCUGTGTT 16CAGAGUUUGUGGAUGUGAUTT 120 PIK4CB18 UUCUCCACUUUAGGGUUGCTGTT 17GCAACCCUAAAGUGGAGAATT 121 PIK4CB19 UGUCACAUGAUGCCGUUGGTGTT 18CCAACGGCAUCAUGUGACATT 122 PIK4CB20 UGAUAGACCGCAUACUGCCATTT 19GGCAGUAUGCGGUCUAUCATT 123 PIK4CB21 UUCCGAGCGGCAAUCAGCCCTTT 20GGCUGAUUGCCGCUCGGAATT 124 PIK4CB22 UUUCGAAUGGUGCUGGAGCCATT 21GCUCCAGCACCAUUCGAAATT 125 PIK4CB23 UGUACAUGUUAAGCAACUGGGTT 22CAGUUGCUUAACAUGUACATT 126 PIK4CB24 UCUACGGACCUCGUACUCCGATT 23GGAGUACGAGGUCCGUAGATT 127 PIK4CB25 UUCCAUUUCCCUUGGGUGGATTT 24CCACCCAAGGGAAAUGGAATT 128 PIK4CB26 UUCUCAGACAAGGGCCCUCTATT 25GAGGGCCCUUGUCUGAGAATT 129 PIK4CB27 UUGCCGAUCGCCAUCAGGGACTT 26CCCUGAUGGCGAUCGGCAATT 130 PIK4CB28 UGGAUCAUCUAGGCAACGGATTT 27CCGUUGCCUAGAUGAUCCATT 131 PIK4CB29 UUCCCAAAUGGACUGCAGUTGTT 28ACUGCAGUCCAUUUGGGAATT 132 PIK4CB30 UCCACUACUGUAUCUCCCATGTT 29UGGGAGAUACAGUAGUGGATT 133 PIK4CB31 UAGGAAGUAAUCGAGCAAGGATT 30CUUGCUCGAUUACUUCCUATT 134 PIK4CB32 AAGAAUCUCAUUCAAUUUCCATT 31GAAAUUGAAUGAGAUUCUUTT 135 PIK4CB33 UAGCUUGGUCCCACGGGAGTGTT 32CUCCCGUGGGACCAAGCUATT 136 PIK4CB34 UUGAACAUGUCGCCAUCCAGGTT 33UGGAUGGCGACAUGUUCAATT 137 PIK4CB35 UCAAGUCCUAAGUACCGAGAATT 34CUCGGUACUUAGGACUUGATT 138 PIK4CB36 AUGACUGACAGGAGCCGCCAATT 35GGCGGCUCCUGUCAGUCAUTT 139 PIK4CB37 UGUUCAUCCCUCUUAGUGGCTTT 36CCACUAAGAGGGAUGAACATT 140 PIK4CB38 UUGGAGUUGAGGACAACAGCCTT 37CUGUUGUCCUCAACUCCAATT 141 PIK4CB39 AAUAAGAGGAUGGCCUGUGGATT 38CACAGGCCAUCCUCUUAUUTT 142 PIK4CB40 UGAUCCGCCGUACUUUCUCCTTT 39GAGAAAGUACGGCGGAUCATT 143 PIK4CB41 AAUUCCACAUGGCUAGGCCAGTT 40GGCCUAGCCAUGUGGAAUUTT 144 PIK4CB42 AUCUGACUUAGAGCGCUGGTGTT 41CCAGCGCUCUAAGUCAGAUTT 145 PIK4CB43 CUCAGUGGUGUAACUGCCGTGTT 42CGGCAGUUACACCACUGAGTT 146 PIK4CB44 UCAGCUUAAAGGCUGACGUCTTT 43ACGUCAGCCUUUAAGCUGATT 147 PIK4CB45 AAGCCGUCAUAGAGUUUGGTGTT 44CCAAACUCUAUGACGGCUUTT 148 PIK4CB46 UCCGUGAUGACACUUAGCAGGTT 45UGCUAAGUGUCAUCACGGATT 149 PIK4CB47 UCGCCUAUGUCAUCCACCGACTT 46CGGUGGAUGACAUAGGCGATT 150 PIK4CB48 UGGAAGGCCCGCCCUUCUCAGTT 47GAGAAGGGCGGGCCUUCCATT 151 PIK4CB49 AACUGGGAGAUGUUGUCACAGTT 48GUGACAACAUCUCCCAGUUTT 152 PIK4CB50 UAGAGACUGCCACGCCUCCATTT 49GGAGGCGUGGCAGUCUCUATT 153 PIK4CB51 UUGACCACUGGUUCAAUCATGTT 50UGAUUGAACCAGUGGUCAATT 154 PIK4CB52 UUAGGGUUGCUGGCUGUUCGTTT 51GAACAGCCAGCAACCCUAATT 155 PIK4CB53 UCUGUGGUCAGCUUAAAGGCTTT 52CCUUUAAGCUGACCACAGATT 156 PIK4CB54 AUUAUCAAUACUCUCGGUGCTTT 53CACCGAGAGUAUUGAUAAUTT 157 PIK4CB55 UUGGUGAGGUACUGGAAGCCGTT 54GCUUCCAGUACCUCACCAATT 158 PIK4CB56 UGUAUGGCUUGAUCCAAAGGGTT 55CUUUGGAUCAAGCCAUACATT 159 PIK4CB57 UUGGAGUUAUACAGGUAUGAATT 56CAUACCUGUAUAACUCCAATT 160 PIK4CB58 UCGAGCUUCCAAGAAUCUCATTT 57GAGAUUCUUGGAAGCUCGATT 161 PIK4CB59 AAAGUUAAUGCUCUGGCGGCATT 58CCGCCAGAGCAUUAACUUUTT 162 PIK4CB60 UAUCAGCCGAAAUCACAAGAATT 59CUUGUGAUUUCGGCUGAUATT 163 PIK4CB61 UUGUCAUAGUUGGGCACAGTGTT 60CUGUGCCCAACUAUGACAATT 164 PIK4CB62 UCCGUAGCUUGGUCCCACGGGTT 61CGUGGGACCAAGCUACGGATT 165 PIK4CB63 UGAGGUUUCGAAUGGUGCUGGTT 62AGCACCAUUCGAAACCUCATT 166 PIK4CB64 UUGUAUGGCUUGAUCCAAAGGTT 63UUUGGAUCAAGCCAUACAATT 167 PIK4CB65 UAAGUACCGAGAACCUACUCTTT 64AGUAGGUUCUCGGUACUUATT 168 PIK4CB66 UUUCCGAGCGGCAAUCAGCCCTT 65GCUGAUUGCCGCUCGGAAATT 169 PIK4CB67 UGAGGUACUGGAAGCCGUCATTT 66GACGGCUUCCAGUACCUCATT 170 PIK4CB68 UCUCAGACAAGGGCCCUCUAGTT 67AGAGGGCCCUUGUCUGAGATT 171 PIK4CB69 UGUAGGCUUGUACUCCAGGCTTT 68CCUGGAGUACAAGCCUACATT 172 PIK4CB70 UUAAUGCUCUGGCGGCAACGGTT 69GUUGCCGCCAGAGCAUUAATT 173 PIK4CB71 GAAUUAUCAAUACUCUCGGTGTT 70CCGAGAGUAUUGAUAAUUCTT 174 PIK4CB72 UUCCACAUGGCUAGGCCAGTATT 71CUGGCCUAGCCAUGUGGAATT 175 PIK4CB73 UGAGGCAUCCGUUCAUACCTCTT 72GGUAUGAACGGAUGCCUCATT 176 PIK4CB74 UUGCUGGCUGUUCGUUUCAGGTT 73UGAAACGAACAGCCAGCAATT 177 PIK4CB75 AACAUGUCGCCAUCCAGGCCGTT 74GCCUGGAUGGCGACAUGUUTT 178 PIK4CB76 UGCUCCGGAGUAGUCAACCAATT 75GGUUGACUACUCCGGAGCATT 179 PIK4CB77 ACUGGUUCAAUCAUGCCACTATT 76GUGGCAUGAUUGAACCAGUTT 180 PIK4CB78 UAGACCGCAUACUGCCAUCCATT 77GAUGGCAGUAUGCGGUCUATT 181 PIK4CB79 UGGAGUUGAGGACAACAGCCTTT  78GCUGUUGUCCUCAACUCCATT 182 PIK4CB80 UAGUUGGGCACAGUGCUGAAGTT 79UCAGCACUGUGCCCAACUATT 183 PIK4CB81 UCAAUACUCUCGGUGCUGGAGTT 80CCAGCACCGAGAGUAUUGATT 184 PIK4CB82 UACUCCGAAUUCGGUUCUCGGTT 81GAGAACCGAAUUCGGAGUATT 185 PIK4CB83 UUACCACAUGAUCCUUCGUGTTT 82ACGAAGGAUCAUGUGGUAATT 186 PIK4CB84 UGGCUAGGCCAGUACCCUCAGTT 83GAGGGUACUGGCCUAGCCATT 187 PIK4CB85 UUCUACGGACCUCGUACUCCGTT 84GAGUACGAGGUCCGUAGAATT 188 PIK4CB86 UGACAGGAGCCGCCAAUUGGGTT 85CAAUUGGCGGCUCCUGUCATT 189 PIK4CB87 UCAGACAAGGGCCCUCUAGGGTT 86CUAGAGGGCCCUUGUCUGATT 190 PIK4CB88 AUUGACCACUGGUUCAAUCATTT 87GAUUGAACCAGUGGUCAAUTT 191 PIK4CB89 UCCGGAGUAGUCAACCAAGTGTT 88CUUGGUUGACUACUCCGGATT 192 PIK4CB90 UCAUGGGUAAUACCACAUUCGTT 89AAUGUGGUAUUACCCAUGATT 193 PIK4CB91 UUCAAUCAUGCCACUAUCAGCTT 90UGAUAGUGGCAUGAUUGAATT 194 PIK4CB92 UCUAGGCAACGGAUCUCACTGTT 91GUGAGAUCCGUUGCCUAGATT 195 PIK4CB93 UGAUCUGGGCAGGUGGAUCATTT 92GAUCCACCUGCCCAGAUCATT 196 PIK4CB94  UAUCAAUACUCUCGGUGCUGGTT 93AGCACCGAGAGUAUUGAUATT 197 PIK4CB95 AAUGCUCUGGCGGCAACGGTGTT 94CCGUUGCCGCCAGAGCAUUTT 198 PIK4CB96 UCCCACGGGAGUGUCGUUGAGTT 95CAACGACACUCCCGUGGGATT 199 PIK4CB97 UUUCUCAGACAAGGGCCCUCTTT 96AGGGCCCUUGUCUGAGAAATT 200 PIK4CB98 AUCUUCUGGGUCUCGUUUGAATT 97CAAACGAGACCCAGAAGAUTT 201 PIK4CB99 UCGUACUCCGAAUUCGGUUCTTT 98AACCGAAUUCGGAGUACGATT 202 PIK4CB100 UUUAGGGUUCCUGGCUGUUCGTT 99AACAGCCAGCAACCCUAAATT 203 PIK4CB101 CUCCUGUAGGAAGUAAUCGAGTT 100CGAUUACUUCCUACAGGAGTT 204 PIK4CB102 UGGUGAGGUACUGGAAGCCGTTT 101GGCUUCCAGUACCUCACCATT 205 PIK4CB103 UCAUCCACCGACCAGGCCUCATT 102AGGCCUGGUCGGUGGAUGATT 206 PIK4CB104 ACUCCGAAUUCGGUUCUCGGGTT 103CGAGAACCGAAUUCGGAGUTT 207 PIK4CB105 UCAGGUAGGGAGCCUUGUCCTTT 104GACAAGGCUCCCUACCUGATT 208

TABLE 2 Duplex siRNA (dsRNA) targeting PIK4CA Duplex Antisense SequenceSEQ ID SEQ ID Name (Guide Sequence) No.: Sense Sequence No.: PIK4CA1GAGCAUCUCUCCCUACCUAUUTT  209 AAUAGGUAGGGAGAGAUGCUCTT 313 PIK4CA2GUGAAGCGAUGUGGAGUUAUUTT 210 AAUAACUCCACAUCGCUUCACTT 314 PIK4CA3CCACAGGCCUCUCCUACUUUUTT 211 AAAAGUAGGAGAGGCCUGUGGTT 315 PIK4CA4GCAGAAAUUUGGCCUGUUUUUTT 212 AAAACAGGCCAAAUUUCUGCTT 316 PIK4CA5SMARTpool, PIK4CA1-A4 PIK4CA1-A4 PIK4CA6 UUCUUAUCUGAGAACAUGGCGTT 213CCAUGUUCUCAGAUAAGAATT 317 PIK4CA7 UUUGGGUUGACUUGCUUCCGATT 214GGAAGCAAGUCAACCCAAATT 318 PIK4CA8 UAGAAGAGGAUGGCGUCCGGATT 215CGGACGCCAUCCUCUUCUATT 319 PIK4CA9 UAUGUGUUGAUCCAGCCUUGGTT 216AAGGCUGGAUCAACACAUATT 320 PIK4CA10 UUGAACUUGGCCAGAUAUGGGTT 217CAUAUCUGGCCAAGUUCAATT 321 PIK4CA11 AUGAUAGCCGACACGUUGGTGTT 218CCAACGUGUCGGCUAUCAUTT 322 PIK4CA12 UUCAGGCACAUCACUAACGGCTT 219CGUUAGUGAUGUGCCUGAATT 323 PIK4CA13 UUCGGAUGAAGUUGUAGCGGGTT 220CGCUACAACUUCAUCCGAATT 324 PIK4CA14 UUCAAGUUCACUAACUCCACATT 221UGGAGUUAGUGAACUUGAATT 325 PIK4CA15 UCAUCCUCGGAGUCUGAGCGGTT 222GCUCAGACUCCGAGGAUGATT 326 PIK4CA16 UUUCUGCUCCACCGUCAUGTGTT 223CAUGACGGUGGAGCAGAAATT 327 PIK4CA17 AGGAAUGUUAGCUCCUCUGTGTT 224CAGAGGAGCUAACAUUCCUTT 328 P1K4CA18 AAGUAGUCAAAGGCAGUGGAGTT 225CCACUGCCUUUGACUACUUTT 329 PIK4CA19 UUCACUUCAGACAGGGCCGACTT 226CGGCCCUGUCUGAAGUGAATT 330 PIK4CA20 UUGUAGUCGAUGUCCAGCACATT 227UGCUGGACAUCGACUACAATT 331 PIK4CA21 UUCGUUCCCAAUGGCUUCUGTTT 228AGAAGCCAUUGGGAACGAATT 332 PIK4CA22 UCGGCGUCGAUGGUGUGCCAGTT 229GGCACACCAUCGACGCCGATT 333 PIK4CA23 AAAGAGGUCCAGGCCGACCAGTT 230GGUCGGCCUGGACCUCUUUTT 334 PIK4CA24 UUAGAUCUCCAGUUGGCCACGTT 231UGGCCAACUGGAGAUCUAATT 335 PIK4CA25 UGUGAUCUCCUCUACCAACTGTT 232GUUGGUAGAGGAGAUCACATT 336 PIK4CA26 UUGGUCAGAGCUGCAGUACTTTT 233GUACUGCAGCUCUGACCAATT 337 PIK4CA27 UGAUGCUUAUGUCUUCACGCATT 234CGUGAAGACAUAAGCAUCATT 338 PIK4CA28 AUUUGGAACCACAUCGGCATGTT 235UGCCGAUGUGGUUCCAAAUTT 339 PIK4CA29 UCCCGGGUCCAACCGAACGAGTT 236CGUUCGGUUGGACCCGGGATT 340 PIK4CA30 UCUGCUUCCUUUAUCUCAGCATT 237CUGAGAUAAAGGAAGCAGATT 341 PIK4CA31 AAGUCGAUCCAGAUGUAGUGGTT 238ACUACAUCUGGAUCGACUUTT 342 PIK4CA32 AAGAGGUCGAUGAUCUGCAGGTT 239UGCAGAUCAUCGACCUCUUTT 343 PIK4CA33 AGAGCCGACAGUUAUGUCCAGTT 240GGACAUAACUGUCGGCUCUTT 344 PIK4CA34 UCCUUGAGUAGGGAACUUUGGTT 241AAAGUUCCCUACUCAAGGATT 345 PIK4CA35 UCCGGCCUGGUCUAGUUCCAGTT 242GGAACUAGACCAGGCCGGATT 346 PIK4CA36 UGUGAUGAGACGCUCGAUCTCTT 243GAUCGAGCGUCUCAUCACATT 347 PIK4CA37 AAGUAGGAGAGGCCUGUGGGTTT 244CCACAGGCCUCUCCUACUUTT 348 PIK4CA38 UCCGGGUGUCCUGAUUAUCTGTT 245GAUAAUCAGGACACCCGGATT 349 PIK4CA39 GAGAUGGUGGACAUGCCGCTGTT 246GCGGCAUGUCCACCAUCUCTT 350 PIK4CA40 UGCCUGCCAGGAGAUCUUCTGTT 247GAAGAUCUCCUGGCAGGCATT 351 PIK4CA41 CUUCUCGCGAAGCACAUUGCGTT 248CAAUGUGCUUCGCGAGAAGTT 352 PIK4CA42 UGCACGGCUAGGUAGGGAGAGTT 249CUCCCUACCUAGCCGUGCATT 353 PIK4CA43 UCUCCCGCAUGAACUACAGGTTT 250CUGUAGUUCAUGCGGGAGATT 354 PIK4CA44 AGAAAUCAAACUCCCGCUGGTTT 251CAGCGGGAGUUUGAUUUCUTT 355 PIK4CA45 UUAUCUGAGAACAUGGCGGTCTT 252CC GCCAUGUUCUCAGAUAATT 356 PIK4CA46 UUGGGUUGACUUGCUUCCGAGTT 253CGGAAGCAAGUCAACCCAATT 357 PIK4CA47 UCUUAUCUGAGAACAUGGCGGTT 254GCCAUGUUCUCAGAUAAGATT 358 PIK4CA48 UCUGAGAACAUGGCGGUCCAATT 255GGACCGCCAUGUUCUCAGATT 359 PIK4CA49 UUGCUUCCGAGGCAGCCAGGGTT 256CUGGCUGCCUCGGAAGCAATT 360 PIK4CA50 UCAAGUUCACUAACUCCACATTT 257GUGGAGUUAGUGAACUUGATT 361 PIK4CA51 AUCUCCACUUGGUCAGAGCTGTT 258GCUCUGACCAAGUGGAGAUTT 362 PIK4CA52 AACGAGACGGGUCACUUCGTTTT 259CGAAGUGACCCGUCUCGUUTT 363 PIK4CA53 UGUGUUGAUCCAGCCUUGGGTTT 260CCAAGGCUGGAUCAACACATT 364 PIK4CA54 UUCUGCUCCACCGUCAUGUGCTT 261ACAUGACGGUGGAGCAGAATT 365 PIK4CA55 UGGAGCAUCGGCGUCGAUGGTTT 262CAUCGACGCCGAUGCUCCATT 366 PIK4CA56 UCGAUGUCCAGCACAAUGGCCTT 263CCAUUGUGCUGGACAUCGATT 367 PIK4CA57 UCGUUCCCAAUGGCUUCUGTGTT 264CAGAAGCCAUUGGGAACGATT 368 PIK4CA58 UAACUCCACAUCGCUUCACCTTT 265GUGAAGCGAUGUGGAGUUATT 369 PIK4CA59 UGAUCUCCUCUACCAACUGATTT 266CAGUUGGUAGAGGAGAUCATT 370 PIK4CA60 UUGGCGAUCUCAAACCGCUGCTT 267AGCGGUUUGAGAUCGCCAATT 371 PIK4CA61 AUGUGUUGAUCCAGCCUUGGGTT 268CAAGGCUGGAUCAACACAUTT 372 PIK4CA62 CUGAUGUACUUAGAUCUCCAGTT 269GGAGAUCUAAGUACAUCAGTT 373 PIK4CA63 UGGAGUAGAUCUUCUCGCGAATT 270CGCGAGAAGAUCUACUCCATT 374 PIK4CA64 UCAGGCACAUCACUAACGGCTTT 271CCGUUAGUGAUGUGCCUGATT 375 PIK4CA65 UAGGCGGCCAUGCUUCGGATGTT 272UCCGAAGCAUGGCCGCCUATT 376 PIK4CA66 GAUGCUUAUGUCUUCACGCAGTT 273GCGUGAAGACAUAAGCAUCTT 377 PIK4CA67 UCUCCAGUUGGCCACGCUGTTTT 274CAGCGUGGCCAACUGGAGATT 378 PIK4CA68 UGAAGUUGUAGCGGGCCUGCTTT 275CAGGCCCGCUACAACUUCATT 379 PIK4CA69 UGAGCUCUGGAGCAUCGGCGTTT 276GCCGAUGCUCCAGAGCUCATT 380 PIK4CA70 AAGGAAUGUUAGCUCCUCUGTTT 277AGAGGAGCUAACAUUCCUUTT 381 PIK4CA71 UGUUCUUAAACCUGGCAGGCATT 278CCUGCCAGGUUUAAGAACATT 382 PIK4CA72 AUGUCCAGCACAAUGGCCUCATT 279AGGCCAUUGUGCUGGACAUTT 383 PIK4CA73 UACAGAAGGAAUGUUAGCUCCTT 280AGCUAACAUUCCUUCUGUATT 384 PIK4CA74 AAGAUCUCCACUUGGUCAGAGTT 281CUGACCAAGUGGAGAUCUUTT 385 PIK4CA75 UCACUUCGUUCCCAAUGGCTTTT 282GCCAUUGGGAACGAAGUGATT 386 PIK4CA76 UGAGACGCUCGAUCUCAGUGGTT 283ACUGAGAUCGAGCGUCUCATT 387 PIK4CA77 UGGCGAUCUCAAACCGCUGCATT 284CAGCGGUUUGAGAUCGCCATT 388 PIK4CA78 UGCCAGGUGACCAGGAACUTGTT  285AGUUCCUGGUCACCUGGCATT 389 PIK4CA79 UACUUAGAUCUCCAGUUGGCCTT 286CCAACUGGAGAUCUAAGUATT 390 PIK4CA80 CUUAUCUGAGAACAUGGCGGTTT 287CGCCAUGUUCUCAGAUAAGTT 391 PIK4CA81 UCCACAUCGCUUCACCUUGAATT 288CAAGGUGAAGCGAUGUGGATT 392 PIK4CA82 UCGGAUGAAGUUGUAGCGGGCTT 289CCGCUACAACUUCAUCCGATT 393 PIK4CA83 AGUGGAGUAGAUCUUCUCGCGTT 290CGAGAAGAUCUACUCCACUTT 394 PIK4CA84 CUUCGUUCCCAAUGGCUUCTGTT 291GAAGCCAUUGGGAACGAAGTT 395 PIK4CA85 AAGAGGAUGGCGUCCGGAGGGTT 292CUCCGGACGCCAUCCUCUUTT 396 PIK4CA86 GUGGAGUAGAUCUUCUCGCGATT 293GCGAGAAGAUCUACUCCACTT 397 PIK4CA87 AGACGGGUCACUUCGUUCCCATT 294GGAACGAAGUGACCCGUCUTT 398 PIK4CA88 AGGAAGUCGAUCCAGAUGUAGTT 295ACAUCUGGAUCGACUUCCUTT 399 PIK4CA89 UUUGGAACCACAUCGGCAUGCTT 296AUGCCGAUGUGGUUCCAAATT 400 PIK4CA90 UGAUGAGACGCUCGAUCUCAGTT 297GAGAUCGAGCGUCUCAUCATT 401 PIK4CA91 CUGUAGGCGGCCAUGCUUCGGTT 298GAAGCAUGGCCGCCUACAGTT 402 PIK4CA92 UCUCAAACCGCUGCACCAGGATT 299CUGGUGCAGCGGUUUGAGATT 403 PIK4CA93 AAGGAGCCUGUGAUCUCCUCTTT 300AGGAGAUCACAGGCUCCUUTT 404 PIK4CA94 AGCUGAAGUAGUCAAAGGCAGTT 301GCCUUUGACUACUUCAGCUTT 405 PIK4CA95 AUGAGACGCUCGAUCUCAGTGTT 302CUGAGAUCGAGCGUCUCAUTT 406 PIK4CA96 UUCCCAAUGGCUUCUGUGUTCTT 303ACACAGAAGCCAUUGGGAATT 407 PIK4CA97 UGUCCAGCACAAUGGCCUCAGTT 304GAGGCCAUUGUGCUGGACATT 408 PIK4CA98 UGGGUUGACUUGCUUCCGAGGTT 305UCGGAAGCAAGUCAACCCATT 409 PIK4CA99 ACUAACUCCACAUCGCUUCACTT 306GAAGCGAUGUGGAGUUAGUTT 410 PIK4CA100 UGGUCAGAGCUGCAGUACUTGTT 307AGUACUGCAGCUCUGACCATT 411 PIK4CA101 CCUGAUUUCUUGGAGAUGGTGTT 308CCAUCUCCAAGAAAUCAGGTT 412 PIK4CA102 UAGUCGAUGUCCAGCACAATGTT 309UUGUGCUGGACAUCGACUATT 413 PIK4CA103 AAGUUGUAGCGGGCCUGCUGGTT 310AGCAGGCCCGCUACAACUUTT 414 PIK4CA104 UGCACUCAUCCUCGGAGUCTGTT 311GACUCCGAGGAUGAGUGCATT 415 PIK4CA105 AUCUCCCGCAUGAACUACAGGTT 312UGUAGUUCAUGCGGGAGAUTT 416

The skilled person is well aware that dsRNAs comprising a duplexstructure of between 20 and 23, but specifically 21, base pairs havebeen recognized as particularly effective in inducing RNA interference(Elbashir et al., EMBO 2001, 20:6877-6888). However, others have foundthat shorter or longer dsRNAs can be effective as well. In theembodiments described above, by virtue of the nature of theoligonucleotide sequences provided in Table 1 or Table 2, the dsRNAs ofthe invention can comprise at least one strand of a length of minimally21 nt. It can be reasonably expected that shorter dsRNAs comprising oneof the sequences of Table 1 or Table 2 minus only a few nucleotides onone or both ends may be similarly effective as compared to the dsRNAsdescribed above. Hence, dsRNAs comprising a partial sequence of at least15, 16, 17, 18, 19, 20, or more contiguous nucleotides from one of thesequences of Table 1 or Table 2 and differing in their ability toinhibit the expression of the PIK4CB or PIK4CA gene in a FACS assay orother assay as described herein below by not more than 5, 10, 15, 20,25, or 30% inhibition from a dsRNA comprising the full sequence, arecontemplated by the invention. Further dsRNAs that cleave within thetarget sequence provided in Table 1 or Table 2 can readily be made usingthe reference sequence and the target sequence provided.

In addition, the RNAi agents provided in Table 1 or Table 2 identify auseful site in the PIK4CB or PIK4CA mRNA that is particularlysusceptible to RNAi based cleavage. As such the present inventionfurther includes RNAi agents that target within the sequence targeted byone of the agents of the present invention. As used herein a second RNAiagent is said to target within the sequence of a first RNAi agent if thesecond RNAi agent cleaves the message anywhere within the mRNA that iscomplementary to the antisense strand of the first RNAi agent. Such asecond agent will generally consist of at least 15 contiguousnucleotides from one of the sequences provided in Table 1 or Table 2coupled to additional nucleotide sequences taken from the regioncontiguous to the selected sequence in the target gene. For example, thelast 15 nucleotides of SEQ ID NO: 5 combined with the next 6 nucleotidesfrom the PIK4CB gene would produce a single strand agent of 21nucleotides that is based on one of the sequences provided in Table 1.Based on this single strand, a complementary sense strand could beeasily generated. It would cleave the target mRNA in the samesensitivity region as the original SEQ ID NO: 5 duplex. The same couldbe done for PIK4CA based on sequences provided in Table 2.

The dsRNA of the invention can contain one or more mismatches to thetarget sequence. In a preferred embodiment, the dsRNA of the inventioncontains no more than 3 mismatches. If the antisense strand of the dsRNAcontains mismatches to a target sequence, it is preferable that the areaof mismatch not be located in the center of the region ofcomplementarity. If the antisense strand of the dsRNA containsmismatches to the target sequence, it is preferable that the mismatch berestricted to 5 nucleotides from either end, for example 5, 4, 3, 2, or1 nucleotide from either the 5′ or 3′ end of the region ofcomplementarity. For example, for a 23 nucleotide dsRNA strand which iscomplementary to a region of the PIK4CB target gene, the dsRNA generallydoes not contain any mismatch within the central 13 nucleotides. Themethods described within the invention can be used to determine whethera dsRNA containing a mismatch to a target sequence is effective inreducing expression of PIK4CB in a cell. Consideration of the efficacyof dsRNAs with mismatches in inhibiting expression of PIK4CB isimportant, especially if the particular region of complementarity inPIK4CB is known to have polymorphic sequence variation in humans. Thesame analysis can be made for dsRNA targeting PIK4CA.

In one embodiment, at least one end of the dsRNA has a single-strandednucleotide overhang of 1 to 4, generally 1 or 2 nucleotides. dsRNAshaving at least one nucleotide overhang have unexpectedly superiorinhibitory properties than their blunt-ended counterparts. Moreover, thepresence of only one nucleotide overhang strengthens the interferenceactivity of the dsRNA, without affecting its overall stability. dsRNAhaving only one overhang has proven particularly stable and effective invivo, as well as in a variety of cells, cell culture mediums, blood, andserum. Generally, the single-stranded overhang is located at the3′-terminal end of the antisense strand or, alternatively, at the3′-terminal end of the sense strand. The dsRNA may also have a bluntend, generally located at the 5′-end of the antisense strand. SuchdsRNAs have improved stability and inhibitory activity, thus allowingadministration at low dosages, i.e., less than 5 mg/kg body weight ofthe recipient per day. Generally, the antisense strand of the dsRNA hasa nucleotide overhang at the 3′-end. In another embodiment, one or moreof the nucleotides in the overhang is replaced with a nucleosidethiophosphate.

In Table 1 and Table 2, matched pairs of RNA strands are shown havingtwo thymidine DNA nucleotides on the 3′ end. This T-T motif isillustrated because it is a commonly used motif which tends to lendstability or other desirable properties to siRNA. Thus T-T is a suitableembodiment of the invention. Nonetheless, it is well known by thoseskilled in the art that other arrangements of nucleotides, optionallywith modified internucleoside linkages, chemical modifications orprotective caps can be employed on the 3′ end of an siRNA strand. Thoseskilled in the art know that such modifications lead to improvedfunctionally equivalent molecules because the target sequence of themRNA remains the same, but the changed overhanging nucleotides mayfavourably influence other pharmacological behaviour.

In yet another embodiment, the dsRNA is chemically modified to enhancestability or provide other therapeutic benefits. The nucleic acids ofthe invention may be synthesized and/or modified by methods wellestablished in the art, such as those described in “Current protocols innucleic acid chemistry”, Beaucage, S. L. et al. (Edrs.), John Wiley &Sons, Inc., New York, N.Y., USA, which is hereby incorporated herein byreference. Chemical modifications may include, but are not limited to 2′modifications, modifications at other sites of the sugar or base of anoligonucleotide, introduction of non-natural bases into theolibonucleotide chain, covalent attachment to a ligand or chemicalmoiety, and replacement of internucleotide phosphate linkages withalternate linkages such as thiophosphates. More than one suchmodification may be employed.

Chemical linking of the two separate dsRNA strands may be achieved byany of a variety of well-known techniques, for example by introducingcovalent, ionic or hydrogen bonds; hydrophobic interactions, van derWaals or stacking interactions; by means of metal-ion coordination, orthrough use of purine analogues. Generally, the chemical groups that canbe used to modify the dsRNA include, without limitation, methylene blue;bifunctional groups, generally bis-(2-chloroethyl)amine;N-acetyl-N′-(p-glyoxylbenzoyl)cystamine; 4-thiouracil; and psoralen. Inone embodiment, the linker is a hexa-ethylene glycol linker. In thiscase, the dsRNA are produced by solid phase synthesis and thehexa-ethylene glycol linker is incorporated according to standardmethods (e.g., Williams, D. J., and K. B. Hall, Biochem. (1996)35:14665-14670). In a particular embodiment, the 5′-end of the antisensestrand and the 3′-end of the sense strand are chemically linked via ahexaethylene glycol linker. In another embodiment, at least onenucleotide of the dsRNA comprises a phosphorothioate orphosphorodithioate groups. The chemical bond at the ends of the dsRNA isgenerally formed by triple-helix bonds. Table 1 and Table 2 provideexamples of dsRNA sequences that could be modified according to thesetechniques.

In yet another embodiment, the nucleotides at one or both of the twosingle strands may be modified to prevent or inhibit the degradationactivities of cellular enzymes, such as, for example, withoutlimitation, certain nucleases. Techniques for inhibiting the degradationactivity of cellular enzymes against nucleic acids are known in the artincluding, but not limited to, 2′-amino modifications, 2′-amino sugarmodifications, 2′-F sugar modifications, 2′-F modifications, 2′-alkylsugar modifications, uncharged backbone modifications, morpholinomodifications, 2′-O-methyl modifications, and phosphoramidate (see,e.g., Wagner, Nat. Med. (1995) 1:1116-8). Thus, at least one 2′-hydroxylgroup of the nucleotides on a dsRNA is replaced by a chemical group,generally by a 2′-amino or a 2′-methyl group. Also, at least onenucleotide may be modified to form a locked nucleotide. Such lockednucleotide contains a methylene bridge that connects the 2′-oxygen ofribose with the 4′-carbon of ribose. Oligonucleotides containing thelocked nucleotide are described in Koshkin, A. A., et al., Tetrahedron(1998), 54: 3607-3630) and Obika, S. et al., Tetrahedron Lett. (1998),39: 5401-5404). Introduction of a locked nucleotide into anoligonucleotide improves the affinity for complementary sequences andincreases the melting temperature by several degrees (Braasch, D. A. andD. R. Corey, Chem. Biol. (2001), 8:1-7).

Conjugating a ligand to a dsRNA can enhance its cellular absorption aswell as targeting to a particular tissue or uptake by specific types ofcells. In certain instances, a hydrophobic ligand is conjugated to thedsRNA to facilitate direct permeation of the cellular membrane.Alternatively, the ligand conjugated to the dsRNA is a substrate forreceptor-mediated endocytosis. These approaches have been used tofacilitate cell permeation of antisense oligonucleotides as well asdsRNA agents. For example, cholesterol has been conjugated to variousantisense oligonucleotides resulting in compounds that are substantiallymore active compared to their non-conjugated analogs. See M. ManoharanAntisense & Nucleic Acid Drug Development 2002, 12, 103. Otherlipophilic compounds that have been conjugated to oligonucleotidesinclude 1-pyrene butyric acid, 1,3-bis-O-(hexadecyl)glycerol, andmenthol. One example of a ligand for receptor-mediated endocytosis isfolic acid. Folic acid enters the cell by folate-receptor-mediatedendocytosis. dsRNA compounds bearing folic acid would be efficientlytransported into the cell via the folate-receptor-mediated endocytosis.Li and coworkers report that attachment of folic acid to the 3′-terminusof an oligonucleotide resulted in an 8-fold increase in cellular uptakeof the oligonucleotide. Li, S.; Deshmukh, H. M.; Huang, L. Pharm. Res.1998, 15, 1540. Other ligands that have been conjugated tooligonucleotides include polyethylene glycols, carbohydrate clusters,cross-linking agents, porphyrin conjugates, and delivery peptides.

In certain instances, conjugation of a cationic ligand tooligonucleotides results in improved resistance to nucleases.Representative examples of cationic ligands are propylammonium anddimethylpropylammonium. Interestingly, antisense oligonucleotides werereported to retain their high binding affinity to mRNA when the cationicligand was dispersed throughout the oligonucleotide. See M. ManoharanAntisense & Nucleic Acid Drug Development 2002, 12, 103 and referencestherein.

The ligand-conjugated dsRNA of the invention may be synthesized by theuse of a dsRNA that bears a pendant reactive functionality, such as thatderived from the attachment of a linking molecule onto the dsRNA. Thisreactive oligonucleotide may be reacted directly withcommercially-available ligands, ligands that are synthesized bearing anyof a variety of protecting groups, or ligands that have a linking moietyattached thereto. The methods of the invention facilitate the synthesisof ligand-conjugated dsRNA by the use of, in some preferred embodiments,nucleoside monomers that have been appropriately conjugated with ligandsand that may further be attached to a solid-support material. Suchligand-nucleoside conjugates, optionally attached to a solid-supportmaterial, are prepared according to some preferred embodiments of themethods of the invention via reaction of a selected serum-binding ligandwith a linking moiety located on the 5′ position of a nucleoside oroligonucleotide. In certain instances, an dsRNA bearing an aralkylligand attached to the 3′-terminus of the dsRNA is prepared by firstcovalently attaching a monomer building block to a controlled-pore-glasssupport via a long-chain aminoalkyl group. Then, nucleotides are bondedvia standard solid-phase synthesis techniques to the monomerbuilding-block bound to the solid support. The monomer building blockmay be a nucleoside or other organic compound that is compatible withsolid-phase synthesis.

The dsRNA used in the conjugates of the invention may be convenientlyand routinely made through the well-known technique of solid-phasesynthesis. Equipment for such synthesis is sold by several vendorsincluding, for example, Applied Biosystems (Foster City, Calif.). Anyother means for such synthesis known in the art may additionally oralternatively be employed. It is also known to use similar techniques toprepare other oligonucleotides, such as the phosphorothioates andalkylated derivatives.

Teachings regarding the synthesis of particular modifiedoligonucleotides may be found in the following U.S. patents: U.S. Pat.Nos. 5,138,045 and 5,218,105, drawn to polyamine conjugatedoligonucleotides; U.S. Pat. No. 5,212,295, drawn to monomers for thepreparation of oligonucleotides having chiral phosphorus linkages; U.S.Pat. Nos. 5,378,825 and 5,541,307, drawn to oligonucleotides havingmodified backbones; U.S. Pat. No. 5,386,023, drawn to backbone-modifiedoligonucleotides and the preparation thereof through reductive coupling;U.S. Pat. No. 5,457,191, drawn to modified nucleobases based on the3-deazapurine ring system and methods of synthesis thereof; U.S. Pat.No. 5,459,255, drawn to modified nucleobases based on N-2 substitutedpurines; U.S. Pat. No. 5,521,302, drawn to processes for preparingoligonucleotides having chiral phosphorus linkages; U.S. Pat. No.5,539,082, drawn to peptide nucleic acids; U.S. Pat. No. 5,554,746,drawn to oligonucleotides having β-lactam backbones; U.S. Pat. No.5,571,902, drawn to methods and materials for the synthesis ofoligonucleotides; U.S. Pat. No. 5,578,718, drawn to nucleosides havingalkylthio groups, wherein such groups may be used as linkers to othermoieties attached at any of a variety of positions of the nucleoside;U.S. Pat. Nos. 5,587,361 and 5,599,797, drawn to oligonucleotides havingphosphorothioate linkages of high chiral purity; U.S. Pat. No.5,506,351, drawn to processes for the preparation of 2′-O-alkylguanosine and related compounds, including 2,6-diaminopurine compounds;U.S. Pat. No. 5,587,469, drawn to oligonucleotides having N-2substituted purines; U.S. Pat. No. 5,587,470, drawn to oligonucleotideshaving 3-deazapurines; U.S. Pat. No. 5,223,168, and U.S. Pat. No.5,608,046, both drawn to conjugated 4′-desmethyl nucleoside analogs;U.S. Pat. Nos. 5,602,240, and 5,610,289, drawn to backbone-modifiedoligonucleotide analogs; U.S. Pat. Nos. 6,262,241; and 5,459,255, drawnto, inter alia, methods of synthesizing 2′-fluoro-oligonucleotides.Other favourable modifications are set out in U.S. Pat. No. 6,670,486,PCT Publication Nos. WO2003082255 and WO2005021749.

In the ligand-conjugated dsRNA and ligand-molecule bearingsequence-specific linked nucleosides of the invention, theoligonucleotides and oligonucleosides may be assembled on a suitable DNAsynthesizer utilizing standard nucleotide or nucleoside precursors, ornucleotide or nucleoside conjugate precursors that already bear thelinking moiety, ligand-nucleotide or nucleoside-conjugate precursorsthat already bear the ligand molecule, or non-nucleoside ligand-bearingbuilding blocks.

When using nucleotide-conjugate precursors that already bear a linkingmoiety, the synthesis of the sequence-specific linked nucleosides istypically completed, and the ligand molecule is then reacted with thelinking moiety to form the ligand-conjugated oligonucleotide.Oligonucleotide conjugates bearing a variety of molecules such assteroids, vitamins, lipids and reporter molecules, has previously beendescribed (see Manoharan et al., PCT Application WO 93/07883). In apreferred embodiment, the oligonucleotides or linked nucleosides of theinvention are synthesized by an automated synthesizer usingphosphoramidites derived from ligand-nucleoside conjugates in additionto the standard phosphoramidites and non-standard phosphoramidites thatare commercially available and routinely used in oligonucleotidesynthesis.

The incorporation of a 2′-O-methyl, 2′-O-propyl, 2′-O-allyl,2′-O-aminoalkyl, 2′-O-methoxyethoxy or 2′-deoxy-2′-fluoro group innucleosides of an oligonucleotide may provide enhanced therapeuticproperties to the oligonucleotide, such as enhanced hybridizationkinetics. Further, oligonucleotides containing phosphorothioatebackbones have enhanced nuclease stability. Thus, functionalized, linkednucleosides of the invention can be augmented to include either or botha phosphorothioate backbone or a 2′-O-methyl, 2′-O-ethyl, 2′-O-propyl,2′-O-aminoalkyl, 2′-O-allyl, 2′-O-methoxyethoxy or 2′-deoxy-2′-fluorogroup. A summary listing of some of the oligonucleotide modificationsknown in the art is found at, for example, PCT Publication WO 200370918.

In some embodiments, functionalized nucleoside sequences of theinvention possessing an amino group at the 5′-terminus are preparedusing a DNA synthesizer, and then reacted with an active esterderivative of a selected ligand. Active ester derivatives are well knownto those skilled in the art. Representative active esters includeN-hydrosuccinimide esters, tetrafluorophenolic esters,pentafluorophenolic esters and pentachlorophenolic esters. The reactionof the amino group and the active ester produces an oligonucleotide inwhich the selected ligand is attached to the 5′-position through alinking group. The amino group at the 5′-terminus can be preparedutilizing a 5′-Amino-Modifier C6 reagent. In one embodiment, ligandmolecules may be conjugated to oligonucleotides at the 5′-position bythe use of a ligand-nucleoside phosphoramidite wherein the ligand islinked to the 5′-hydroxy group directly or indirectly via a linker. Suchligand-nucleoside phosphoramidites are typically used at the end of anautomated synthesis procedure to provide a ligand-conjugatedoligonucleotide bearing the ligand at the 5′-terminus.

Examples of modified internucleoside linkages or backbones include, forexample, phosphorothioates, chiral phosphorothioates,phosphorodithioates, phosphotriesters, aminoalkylphosphotriesters,methyl and other alkyl phosphonates including 3′-alkylene phosphonatesand chiral phosphonates, phosphinates, phosphoramidates including3′-amino phosphoramidate and aminoalkylphosphoramidates,thionophosphoramidates, thionoalkylphosphonates,thionoalkylphosphotriesters, and boranophosphates having normal 3′-5′linkages, 2′-5′ linked analogs of these, and those having invertedpolarity wherein the adjacent pairs of nucleoside units are linked 3′-5′to 5′-3′ or 2′-5′ to 5′-2′. Various salts, mixed salts and free-acidforms are also included.

Representative United States patents relating to the preparation of theabove phosphorus-atom-containing linkages include, but are not limitedto, U.S. Pat. Nos. 3,687,808; 4,469,863; 4,476,301; 5,023,243;5,177,196; 5,188,897; 5,264,423; 5,276,019; 5,278,302; 5,286,717;5,321,131; 5,399,676; 5,405,939; 5,453,496; 5,455,233; 5,466,677;5,476,925; 5,519,126; 5,536,821; 5,541,306; 5,550,111; 5,563,253;5,571,799; 5,587,361; 5,625,050; and 5,697,248, each of which is hereinincorporated by reference.

Examples of modified internucleoside linkages or backbones that do notinclude a phosphorus atom therein (i.e., oligonucleosides) havebackbones that are formed by short chain alkyl or cycloalkyl intersugarlinkages, mixed heteroatom and alkyl or cycloalkyl intersugar linkages,or one or more short chain heteroatomic or heterocyclic intersugarlinkages. These include those having morpholino linkages (formed in partfrom the sugar portion of a nucleoside); siloxane backbones; sulfide,sulfoxide and sulfone backbones; formacetyl and thioformacetylbackbones; methylene formacetyl and thioformacetyl backbones; alkenecontaining backbones; sulfamate backbones; methyleneimino andmethylenehydrazino backbones; sulfonate and sulfonamide backbones; amidebackbones; and others having mixed N, O, S and CH₂ component parts. Asnoted in Table 1 and Table 2, a dT-dT pair may be added at the 3′ end ofeither (or both) strand(s) of the dsRNA. The added dT-dT pair in thesesituations are usually not complementary to the target sequence. ThesedT-dT pairs, which may contain phosphorothioate (sulfur) internucleosidelinkages, are added to enhance stability.

Representative United States patents relating to the preparation of theabove oligonucleosides include, but are not limited to, U.S. Pat. Nos.5,034,506; 5,166,315; 5,185,444; 5,214,134; 5,216,141; 5,235,033;5,264,562; 5,264,564; 5,405,938; 5,434,257; 5,466,677; 5,470,967;5,489,677; 5,541,307; 5,561,225; 5,596,086; 5,602,240; 5,610,289;5,602,240; 5,608,046; 5,610,289; 5,618,704; 5,623,070; 5,663,312;5,633,360; 5,677,437; and 5,677,439, each of which is hereinincorporated by reference.

In certain instances, the oligonucleotide may be modified by anon-ligand group. A number of non-ligand molecules have been conjugatedto oligonucleotides in order to enhance the activity, cellulardistribution or cellular uptake of the oligonucleotide, and proceduresfor performing such conjugations are available in the scientificliterature. Such non-ligand moieties have included lipid moieties, suchas cholesterol (Letsinger et al., Proc. Natl. Acad. Sci. USA, 1989,86:6553), cholic acid (Manoharan et al., Bioorg. Med. Chem. Lett., 1994,4:1053), a thioether, e.g., hexyl-5-tritylthiol (Manoharan et al., Ann.N.Y. Acad. Sci., 1992, 660:306; Manoharan et al., Bioorg. Med. Chem.Let., 1993, 3:2765), a thiocholesterol (Oberhauser et al., Nucl. AcidsRes., 1992, 20:533), an aliphatic chain, e.g., dodecandiol or undecylresidues (Saison-Behmoaras et al., EMBO J., 1991, 10:111; Kabanov etal., FEBS Lett., 1990, 259:327; Svinarchuk et al., Biochimie, 1993,75:49), a phospholipid, e.g., di-hexadecyl-rac-glycerol ortriethylammonium 1,2-di-O-hexadecyl-rac-glycero-3-H-phosphonate(Manoharan et al., Tetrahedron Lett., 1995, 36:3651; Shea et al., Nucl.Acids Res., 1990, 18:3777), a polyamine or a polyethylene glycol chain(Manoharan et al., Nucleosides & Nucleotides, 1995, 14:969), oradamantane acetic acid (Manoharan et al., Tetrahedron Lett., 1995,36:3651), a palmityl moiety (Mishra et al., Biochim. Biophys. Acta,1995, 1264:229), or an octadecylamine orhexylamino-carbonyl-oxycholesterol moiety (Crooke et al., J. Pharmacol.Exp. Ther., 1996, 277:923). Representative United States patents thatteach the preparation of such oligonucleotide conjugates have beenlisted above. Typical conjugation protocols involve the synthesis ofoligonucleotides bearing an aminolinker at one or more positions of thesequence. The amino group is then reacted with the molecule beingconjugated using appropriate coupling or activating reagents. Theconjugation reaction may be performed either with the oligonucleotidestill bound to the solid support or following cleavage of theoligonucleotide in solution phase. Purification of the oligonucleotideconjugate by HPLC typically affords the pure conjugate. The use of acholesterol conjugate is particularly preferred since such a moiety canincrease targeting liver cells which are a primary site of positivestranded RNA virus (such as HCV) infection.

The instant disclosure describes a wide variety of embodiments of dsRNAthat are useful to silence PIK4CB expression and thus to preventpositive stranded RNA virus propagation and to treat associateddisorders. While the design of the specific therapeutic agent can take avariety of forms, certain functional characteristics will distinguishpreferred combinations of dsRNA from other combinations of dsRNA. Inparticular, features such as good serum stability, high potency, lack ofinduced immune response, and good drug like behaviour, all measurable bythose skilled in the art, will be tested to identify preferred dsRNA ofthe invention. In some situations, not all of these functional aspectswill be present in the preferred dsRNA combination. But those skilled inthe art are able to optimize these variables and others to selectpreferred compounds of the invention.

The inventors are aware of patterns of chemical modifications which tendto provide significantly improved pharmacological, immunological andulitimately therapeutic benefit. These patterns are observed to improvethe siRNA regardless of the target sequence selected. Table 3 sets outpatterns of chemical modifications preferred for use with the duplexdsRNA set out in Table 1 or Table 2. These patterns are not mutuallyexclusive.

TABLE 3 Preferred Chemical Modifications of siRNA Chemical Changes madeto Changes made to Modification sense strand antisense stand Series(5′-3′) (5′-3′) 1 - dTsdT 3′ - dTsdT 3′ 2 dTsdT 3′, 2′OMe@all Py dTsdT3′, 2′OMe@uA, cA 3 dTsdT 3′, 2′OMe@all Py dTsdT 3′, 2′OMe@uA, cA, uG, uU4 Chol (“exo”) dTsdT 3′ 5 Chol (“endo”) dTsdT 3′, 2′OMe@uA, cA 6 Chol(“endo”) dTsdT 3′, 2′OMe@uA, cA, uG, uU s = phosphorothioate linkage dT= deoxyribothymidine 2′OMe = 2′-O-Methyl modification of RNA Py =pyrimidine nucleotide Chol = cholesterol. “exo” refers to 3′ endlinkage; “endo” means linkage is to an internal nucleoside. uA or cA =indicates at a UA or CA RNA sequence, the U or C receives the indicatedmodification. Same applies to uG and uU.

Vector Encoded RNAi Agents

The dsRNA of the invention can also be expressed from recombinant viralvectors intracellularly in vivo. The recombinant viral vectors of theinvention comprise sequences encoding the dsRNA of the invention and anysuitable promoter for expressing the dsRNA sequences. Suitable promotersinclude, for example, the U6 or H1 RNA pol III promoter sequences andthe cytomegalovirus promoter. Selection of other suitable promoters iswithin the skill in the art. The recombinant viral vectors of theinvention can also comprise inducible or regulatable promoters forexpression of the dsRNA in a particular tissue or in a particularintracellular environment. The use of recombinant viral vectors todeliver dsRNA of the invention to cells in vivo is discussed in moredetail below.

dsRNA of the invention can be expressed from a recombinant viral vectoreither as two separate, complementary RNA molecules, or as a single RNAmolecule with two complementary regions.

Any viral vector capable of accepting the coding sequences for the dsRNAmolecule(s) to be expressed can be used, for example vectors derivedfrom adenovirus (AV); adeno-associated virus (AAV); retroviruses (e.g,lentiviruses (LV), Rhabdoviruses, murine leukemia virus); herpes virus,and the like. The tropism of viral vectors can be modified bypseudotyping the vectors with envelope proteins or other surfaceantigens from other viruses, or by substituting different viral capsidproteins, as appropriate.

For example, lentiviral vectors of the invention can be pseudotyped withsurface proteins from vesicular stomatitis virus (VSV), rabies, Ebola,Mokola, and the like. AAV vectors of the invention can be made to targetdifferent cells by engineering the vectors to express different capsidprotein serotypes. For example, an AAV vector expressing a serotype 2capsid on a serotype 2 genome is called AAV 2/2. This serotype 2 capsidgene in the AAV 2/2 vector can be replaced by a serotype 5 capsid geneto produce an AAV 2/5 vector. Techniques for constructing AAV vectorswhich express different capsid protein serotypes are within the skill inthe art; see, e.g., Rabinowitz J E et al. (2002), J Virol 76:791-801,the entire disclosure of which is herein incorporated by reference.

Selection of recombinant viral vectors suitable for use in theinvention, methods for inserting nucleic acid sequences for expressingthe dsRNA into the vector, and methods of delivering the viral vector tothe cells of interest are within the skill in the art. See, for example,Dornburg R (1995), Gene Therap. 2: 301-310; Eglitis M A (1988),Biotechniques 6: 608-614; Miller A D (1990), Hum Gene Therap. 1: 5-14;Anderson W F (1998), Nature 392: 25-30; and Rubinson D A et al., Nat.Genet. 33: 401-406, the entire disclosures of which are hereinincorporated by reference.

Preferred viral vectors are those derived from AV and AAV. In aparticularly preferred embodiment, the dsRNA of the invention isexpressed as two separate, complementary single-stranded RNA moleculesfrom a recombinant AAV vector comprising, for example, either the U6 orH1 RNA promoters, or the cytomegalovirus (CMV) promoter.

A suitable AV vector for expressing the dsRNA of the invention, a methodfor constructing the recombinant AV vector, and a method for deliveringthe vector into target cells, are described in Xia H et al. (2002), Nat.Biotech. 20: 1006-1010.

Suitable AAV vectors for expressing the dsRNA of the invention, methodsfor constructing the recombinant AV vector, and methods for deliveringthe vectors into target cells are described in Samulski Ret al. (1987),J. Virol. 61: 3096-3101; Fisher K Jet al. (1996), J. Virol, 70: 520-532;Samulski R et al. (1989), J. Virol. 63: 3822-3826; U.S. Pat. No.5,252,479; U.S. Pat. No. 5,139,941; International Patent Application No.WO 94/13788; and International Patent Application No. WO 93/24641, theentire disclosures of which are herein incorporated by reference.

Pharmaceutical Compositions Comprising dsRNA

In one embodiment, the invention provides pharmaceutical compositionscomprising the dsRNA described herein and a pharmaceutically acceptablecarrier. In another embodiment, the invention comprises a combination ofthe dsRNA and another active principle ingredient. The pharmaceuticalcomposition comprising the combination of dsRNA and active principleingredient is useful for treating a disease or disorder associated withthe pathological processes mediated by positive stranded RNA virusinfection.

The pharmaceutical compositions of the invention are administered indosages sufficient to inhibit expression or activity of the PIK4CB orPIK4CA gene. The present inventors have determined that compositionscomprising the dsRNA of the invention can be administered atsurprisingly low dosages. A dosage of 5 mg dsRNA per kilogram bodyweight of recipient per day is sufficient to inhibit or suppress of thePIK4CB or PIK4CA gene.

In general, a suitable dose of each dsRNA in the combination will be inthe range of 0.01 to 5.0 milligrams per kilogram body weight of therecipient per day, generally in the range of 1 microgram to 1 mg perkilogram body weight per day. The pharmaceutical composition may beadministered once daily, or the dsRNA may be administered as two, three,or more sub-doses at appropriate intervals throughout the day or evenusing continuous infusion or delivery through a controlled releaseformulation. In that case, the dsRNA contained in each sub-dose must becorrespondingly smaller in order to achieve the total daily dosage. Thedosage unit can also be compounded for delivery over several days, e.g.,using a conventional sustained release formulation which providessustained release of the dsRNA over a several day period. In thisembodiment, the dosage unit contains a corresponding multiple of thedaily dose.

The skilled artisan will appreciate that certain factors may influencethe dosage and timing required to effectively treat a subject, includingbut not limited to the severity of the disease or disorder, previoustreatments, the general health and/or age of the subject, and otherdiseases present. Moreover, treatment of a subject with atherapeutically effective amount of a composition can include a singletreatment or a series of treatments. Estimates of effective dosages andin vivo half-lives for the individual dsRNAs encompassed by theinvention can be made using conventional methodologies or on the basisof in vivo testing using an appropriate animal model, as describedelsewhere herein.

The inventors recognize that for a variety of reasons, it may bedesirable to treat positive stranded RNA virus infection with acombination of two or more dsRNA. One dsRNA is selected from among thedsRNA of the invention, and another dsRNA is selected from among thosedsRNA known to target the positive stranded RNA virus itself dsRNAtargeting HCV or HPV or other positive stranded RNA viruses may beidentified from publications in the prior art. A pharmaceuticalcomposition of the invention comprising more than one type of dsRNAwould be expected to contain dosages of individual dsRNA as describedherein.

Combinations of dsRNA may be provided together in a single dosage formpharmaceutical composition. Alternatively, combination dsRNA may beprovided in separate dosage forms, in which case they may beadministered at the same time or at different times, and possibly bydifferent means. The invention therefore contemplates pharmaceuticalcompositions comprising the desired combinations of dsRNA of theinvention; and it also contemplates pharmaceutical compositions ofsingle dsRNA which are intended to be provided as part of a combinationregimen. In this latter case, the combination therapy invention isthereby a method of administering rather than a composition of matter.

Advances in mouse genetics have generated a number of mouse models forthe study of various human diseases, such as pathological processesmediated by HCV infection. Such models are used for in vivo testing ofdsRNA, as well as for determining a therapeutically effective dose, andpreferred combinations of dsRNA.

Any method can be used to administer a dsRNA of the present invention toa mammal containing cells infected with HCV. For example, administrationcan be topical (e.g., vaginal, transdermal, etc); oral; or parenteral(e.g., by subcutaneous, intraventricular, intramuscular, orintraperitoneal injection, or by intravenous drip). Administration canbe rapid (e.g., by injection), or can occur over a period of time (e.g.,by slow infusion or administration of slow release formulations).

For topical administration, dsRNA can be formulated into compositionssuch as sterile and non-sterile aqueous solutions, non-aqueous solutionsin common solvents such as alcohols, or solutions in liquid or solid oilbases. Such solutions also can contain buffers, diluents, and othersuitable additives. Compositions for topical administration can beformulated in the form of transdermal patches, ointments, lotions,creams, gels, drops, suppositories, sprays, liquids, and powders. Gelsand creams may be formulated using polymers and permeabilizers known inthe art.

For parenteral, intrathecal, or intraventricular administration, a dsRNAmolecule can be formulated into compositions such as sterile aqueoussolutions, which also can contain buffers, diluents, and other suitableadditives (e.g., penetration enhancers, carrier compounds, and otherpharmaceutically acceptable carriers).

In addition, dsRNA molecules of the invention can be administered to amammal containing positive stranded RNA virus infected cells usingnon-viral methods, such as biologic or abiologic means as described in,for example, U.S. Pat. No. 6,271,359. Abiologic delivery can beaccomplished by a variety of methods including, without limitation, (1)loading liposomes with a dsRNA acid molecule provided herein; (2)complexing a dsRNA molecule with lipids or liposomes to form nucleicacid-lipid or nucleic acid-liposome complexes; or (3) providing apolymer, nanoparticle or nanoemulsion based therapeutic delivery system.These techniques are generally well known in the art in other contexts.A brief description follows.

The liposome or lipid complex can be composed of cationic and neutrallipids commonly used to transfect cells in vitro. Cationic lipids cancomplex (e.g., charge-associate) with negatively charged nucleic acidsto form liposomes. Examples of cationic liposomes include, withoutlimitation, lipofectin, lipofectamine, lipofectace, and DOTAP.Procedures for forming liposomes are well known in the art. Liposomecompositions can be formed, for example, from phosphatidylcholine,dimyristoyl phosphatidylcholine, dipalmitoyl phosphatidylcholine,dimyristoyl phosphatidylglycerol, or dioleoyl phosphatidylethanolamine.Numerous lipophilic agents are commercially available, includingLipofectin® (Invitrogen/Life Technologies, Carlsbad, Calif.) andEffectene™ (Qiagen, Valencia, Calif.). In addition, systemic deliverymethods can be optimized using commercially available cationic lipidssuch as DDAB or DOTAP, each of which can be mixed with a neutral lipidsuch as DOPE or cholesterol. In some cases, liposomes such as thosedescribed by Templeton et al. (Nature Biotechnology, 15: 647-652 (1997))can be used. In some embodiments, the dosage will be fully encapsulatedin the liposome, such as in the SNALP described in Morrissey et al. Nat.Biotechnol. 2005 August; 23(8):1002-7. Epub 2005 Jul. 24. See alsoWheeler, J. J. et al. 1999. Gene Ther. 6, 271-281. In other embodiments,polycations such as polyethyleneimine can be used to achieve delivery invivo and ex vivo (Boletta et al., J. Am. Soc. Nephrol. 7: 1728 (1996)).Additional information regarding the use of liposomes to deliver nucleicacids can be found in U.S. Pat. No. 6,271,359, PCT Publication WO96/40964 and Morrissey, D. et al. 2005. Nat. Biotechnol. 23(8):1002-7.

Biologic delivery can be accomplished by a variety of methods including,without limitation, the use of viral vectors. For example, viral vectors(e.g., adenovirus and herpesvirus vectors) can be used to deliver dsRNAmolecules to skin cells and cervical cells. Standard molecular biologytechniques can be used to introduce one or more of the dsRNAs providedherein into one of the many different viral vectors previously developedto deliver nucleic acid to cells. These resulting viral vectors can beused to deliver the one or more dsRNAs to cells by, for example,infection.

dsRNAs of the present invention can be formulated in a pharmaceuticallyacceptable carrier or diluent. A “pharmaceutically acceptable carrier”(also referred to herein as an “excipient”) is a pharmaceuticallyacceptable solvent, suspending agent, or any other pharmacologicallyinert vehicle. Pharmaceutically acceptable carriers can be liquid orsolid, and can be selected with the planned manner of administration inmind so as to provide for the desired bulk, consistency, and otherpertinent transport and chemical properties. Typical pharmaceuticallyacceptable carriers include, by way of example and not limitation:water; saline solution; binding agents (e.g., polyvinylpyrrolidone orhydroxypropyl methylcellulose); fillers (e.g., lactose and other sugars,gelatin, or calcium sulfate); lubricants (e.g., starch, polyethyleneglycol, or sodium acetate); disintegrates (e.g., starch or sodium starchglycolate); and wetting agents (e.g., sodium lauryl sulfate).

In addition, dsRNA that target the PIK4CB gene expression can beformulated into compositions containing the dsRNA admixed, encapsulated,conjugated, or otherwise associated with molecules (including smallmolecule therapeutic agents), molecular structures, or mixtures ofnucleic acids. For example, a composition containing one or more dsRNAagentsof the invention can contain other therapeutic agents such asanti-inflammatory drugs (e.g., nonsteroidal anti-inflammatory drugs andcorticosteroids) and antiviral drugs (e.g., ribivirin, vidarabine,acyclovir, and ganciclovir).

Toxicity and therapeutic efficacy of such compounds can be determined bystandard pharmaceutical procedures in cell cultures or experimentalanimals, e.g., for determining the LD50 (the dose lethal to 50% of thepopulation) and the ED50 (the dose therapeutically effective in 50% ofthe population). The dose ratio between toxic and therapeutic effects isthe therapeutic index and it can be expressed as the ratio LD50/ED50.Compounds which exhibit high therapeutic indices are preferred.

The data obtained from cell culture assays and animal studies can beused in formulation a range of dosage for use in humans. The dosage ofcompositions of the invention lies generally within a range ofcirculating concentrations that include the ED50 with little or notoxicity. The dosage may vary within this range depending upon thedosage form employed and the route of administration utilized. For anycompound used in the method of the invention, the therapeuticallyeffective dose can be estimated initially from cell culture assays. Adose may be formulated in animal models to achieve a circulating plasmaconcentration range of the compound or, when appropriate, of thepolypeptide product of a target sequence (e.g., achieving a decreasedconcentration of the polypeptide) that includes the IC50 (i.e., theconcentration of the test compound which achieves a half-maximalinhibition of symptoms) as determined in cell culture. Such informationcan be used to more accurately determine useful doses in humans. Levelsin plasma may be measured, for example, by high performance liquidchromatography.

In addition to their administration individually or as a plurality, asdiscussed above, the dsRNAs of the invention can be administered incombination with other known agents effective in treatment ofpathological processes mediated by HCV infection. In any event, theadministering physician can adjust the amount and timing of dsRNAadministration on the basis of results observed using standard measuresof efficacy known in the art or described herein.

Combinations of dsRNA can be tested in vitro and in vivo using the samemethods employed for identification of preferred single dsRNA. Suchcombinations may be selected based on a purely bioinformatics basis.Alternatively, such combinations may be selected based on in vitro or invivo evaluations along the lines of those described herein for singledsRNA agents. A preferred assay for testing combinations of dsRNA is theassay set out in the Examples below.

Methods for Treating Diseases Caused by Positive Stranded RNA VirusInfection

The methods and compositions described herein can be used to treatdiseases and conditions caused by positive stranded RNA virus infection(such as HCV), which can be the result of clinical or sub-clinicalinfections.

In overview, the method of treating infection by a positive stranded RNAviruses comprises administering to a patient in need thereof, a compoundwhich selectively inhibits the activity of the phosphatidylinositol4-kinase (PI4K). Such compounds can be selected from among smallmolecules, dsRNA, a DNA antisense DNA, a ribozyme, or a DNA vectorencoding the foregoing. Small molecule agents which are selective forPIK4CB and/or PIK4CA in the liver would be of considerable interest fortherapeutic purposes in the treatment of infection by positive strandedRNA viruses.

Such diseases and conditions, herein sometimes called “pathologicalprocesses mediated by positive stranded RNA virus infection”. The majorhepatological consequence of HCV infection is cirrhosis andcomplications thereof including haemorrhage, hepatic insufficiency, andhepatocellular carcinoma. Fibrosis is the result of chronic inflammationcausing the deposition of extracellular matrix component distorting thehepatic architecture and blocking microcirculation and liver function.As cirrhosis progresses and the fibrotic tissue builds up, severenecroinflamatory activity ensues and steatosis begins. Steatosis leadsto extrahepatic pathologies including diabetes, protein malnutrition,hypertension, cell toxins, obesity, and anoxia. As fibrosis andsteatosis becomes severe the liver will eventually fail and requireliver transplantation.

In this specification, a “method of treating” or “method of treatment”is intended to refer to methods which treat, prevent, are prophylacticagainst, or reduce the significance of (at an objective or subjectivelevel) one or more symptom of, the disease, disorder or condition whichis indicated by the phrase.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of the invention, suitable methods and materials aredescribed below. All publications, patent applications, patents, andother references mentioned herein are incorporated by reference in theirentirety. In case of conflict, the present specification, includingdefinitions, will control. In addition, the materials, methods, andexamples are illustrative only and not intended to be limiting.

EXAMPLES Example 1 dsRNA Synthesis

Source of Reagents

Where the source of a reagent is not specifically given herein, suchreagent may be obtained from any supplier of reagents for molecularbiology at a quality/purity standard for application in molecularbiology.

siRNA Synthesis

Single-stranded RNAs were produced by solid phase synthesis on a scaleof 1 mmole using an Expedite 8909 synthesizer (Applied Biosystems,Applera Deutschland GmbH, Darmstadt, Germany) and controlled pore glass(CPG, 500 Å, Proligo Biochemie GmbH, Hamburg, Germany) as solid support.RNA and RNA containing 2′-O-methyl nucleotides were generated by solidphase synthesis employing the corresponding phosphoramidites and2′-O-methyl phosphoramidites, respectively (Proligo Biochemie GmbH,Hamburg, Germany). These building blocks were incorporated at selectedsites within the sequence of the oligoribonucleotide chain usingstandard nucleoside phosphoramidite chemistry such as described inCurrent protocols in nucleic acid chemistry, Beaucage, S. L. et al.(Edrs.), John Wiley & Sons, Inc., New York, N.Y., USA. Phosphorothioatelinkages were introduced by replacement of the iodine oxidizer solutionwith a solution of the Beaucage reagent (Chruachem Ltd, Glasgow, UK) inacetonitrile (1%). Further ancillary reagents were obtained fromMallinckrodt Baker (Griesheim, Germany).

Deprotection and purification of the crude oligoribonucleotides by anionexchange HPLC were carried out according to established procedures.Yields and concentrations were determined by UV absorption of a solutionof the respective RNA at a wavelength of 260 nm using a spectralphotometer (DU 640B, Beckman Coulter GmbH, Unterschleiβheim, Germany).Double stranded RNA was generated by mixing an equimolar solution ofcomplementary strands in annealing buffer (20 mM sodium phosphate, pH6.8; 100 mM sodium chloride), heated in a water bath at 85-90° C. for 3minutes and cooled to room temperature over a period of 3-4 hours. Theannealed RNA solution was stored at −20° C. until use.

For the synthesis of 3′-cholesterol-conjugated siRNAs (herein referredto as -Chol-3′), an appropriately modified solid support was used forRNA synthesis. The modified solid support was prepared as follows:

Diethyl-2-azabutane-1,4-dicarboxylate AA

A 4.7 M aqueous solution of sodium hydroxide (50 mL) was added into astirred, ice-cooled solution of ethyl glycinate hydrochloride (32.19 g,0.23 mole) in water (50 mL). Then, ethyl acrylate (23.1 g, 0.23 mole)was added and the mixture was stirred at room temperature untilcompletion of the reaction was ascertained by TLC. After 19 h thesolution was partitioned with dichloromethane (3×100 mL). The organiclayer was dried with anhydrous sodium sulfate, filtered and evaporated.The residue was distilled to afford AA (28.8 g, 61%).

3-{Ethoxycarbonylmethyl-[6-(9H-fluoren-9-ylmethoxycarbonyl-amino)-hexanoyl]-amino}-propionicacid ethyl ester AB

Fmoc-6-amino-hexanoic acid (9.12 g, 25.83 mmol) was dissolved indichloromethane (50 mL) and cooled with ice. Diisopropylcarbodiimde(3.25 g, 3.99 mL, 25.83 mmol) was added to the solution at 0° C. It wasthen followed by the addition of Diethyl-azabutane-1,4-dicarboxylate (5g, 24.6 mmol) and dimethylamino pyridine (0.305 g, 2.5 mmol). Thesolution was brought to room temperature and stirred further for 6 h.Completion of the reaction was ascertained by TLC. The reaction mixturewas concentrated under vacuum and ethyl acetate was added to precipitatediisopropyl urea. The suspension was filtered. The filtrate was washedwith 5% aqueous hydrochloric acid, 5% sodium bicarbonate and water. Thecombined organic layer was dried over sodium sulfate and concentrated togive the crude product which was purified by column chromatography (50%EtOAC/Hexanes) to yield 11.87 g (88%) of AB.

3-[(6-Amino-hexanoyl)-ethoxycarbonylmethyl-amino]-propionic acid ethylester AC

3-{Ethoxycarbonylmethyl-[6-(9H-fluoren-9-ylmethoxycarbonylamino)-hexanoyl]-amino}-propionicacid ethyl ester AB (11.5 g, 21.3 mmol) was dissolved in 20% piperidinein dimethylformamide at 0° C. The solution was continued stirring for 1h. The reaction mixture was concentrated under vacuum, water was addedto the residue, and the product was extracted with ethyl acetate. Thecrude product was purified by conversion into its hydrochloride salt.

3-({6-[17-(1,5-Dimethyl-hexyl)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-yloxycarbonylamino]-hexanoyl}ethoxycarbonylmethyl-amino)-propionicacid ethyl ester AD

The hydrochloride salt of3-[(6-Amino-hexanoyl)-ethoxycarbonylmethyl-amino]-propionic acid ethylester AC (4.7 g, 14.8 mmol) was taken up in dichloromethane. Thesuspension was cooled to 0° C. on ice. To the suspensiondiisopropylethylamine (3.87 g, 5.2 mL, 30 mmol) was added. To theresulting solution cholesteryl chloroformate (6.675 g, 14.8 mmol) wasadded. The reaction mixture was stirred overnight. The reaction mixturewas diluted with dichloromethane and washed with 10% hydrochloric acid.The product was purified by flash chromatography (10.3 g, 92%).

1-{6-[17-(1,5-Dimethyl-hexyl)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-yloxycarbonylamino]-hexanoyl}-4-oxo-pyrrolidine-3-carboxylicacid ethyl ester AE

Potassium t-butoxide (1.1 g, 9.8 mmol) was slurried in 30 mL of drytoluene. The mixture was cooled to 0° C. on ice and 5 g (6.6 mmol) ofdiester AD was added slowly with stirring within 20 mins. Thetemperature was kept below 5° C. during the addition. The stirring wascontinued for 30 mins at 0° C. and 1 mL of glacial acetic acid wasadded, immediately followed by 4 g of NaH₂PO₄.H₂O in 40 mL of water Theresultant mixture was extracted twice with 100 mL of dichloromethaneeach and the combined organic extracts were washed twice with 10 mL ofphosphate buffer each, dried, and evaporated to dryness. The residue wasdissolved in 60 mL of toluene, cooled to 0° C. and extracted with three50 mL portions of cold pH 9.5 carbonate buffer. The aqueous extractswere adjusted to pH 3 with phosphoric acid, and extracted with five 40mL portions of chloroform which were combined, dried and evaporated todryness. The residue was purified by column chromatography using 25%ethylacetate/hexane to afford 1.9 g of b-ketoester (39%).

[6-(3-Hydroxy-4-hydroxymethyl-pyrrolidin-1-yl)-6-oxo-hexyl]-carbamicacid17-(1,5-dimethyl-hexyl)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-ylester AF

Methanol (2 mL) was added dropwise over a period of 1 h to a refluxingmixture of b-ketoester AE (1.5 g, 2.2 mmol) and sodium borohydride(0.226 g, 6 mmol) in tetrahydrofuran (10 mL). Stirring was continued atreflux temperature for 1 h. After cooling to room temperature, 1 N HCl(12.5 mL) was added, the mixture was extracted with ethylacetate (3×40mL). The combined ethylacetate layer was dried over anhydrous sodiumsulfate and concentrated under vacuum to yield the product which waspurified by column chromatography (10% MeOH/CHCl₃) (89%).

(6-{3-[Bis-(4-methoxy-phenyl)-phenyl-methoxymethyl]-4-hydroxy-pyrrolidin-1-yl}-6-oxo-hexyl)-carbamicacid17-(1,5-dimethyl-hexyl)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-ylester AG

Diol AF (1.25 gm 1.994 mmol) was dried by evaporating with pyridine (2×5mL) in vacuo. Anhydrous pyridine (10 mL) and4,4′-dimethoxytritylchloride (0.724 g, 2.13 mmol) were added withstirring. The reaction was carried out at room temperature overnight.The reaction was quenched by the addition of methanol. The reactionmixture was concentrated under vacuum and to the residue dichloromethane(50 mL) was added. The organic layer was washed with 1M aqueous sodiumbicarbonate. The organic layer was dried over anhydrous sodium sulfate,filtered and concentrated. The residual pyridine was removed byevaporating with toluene. The crude product was purified by columnchromatography (2% MeOH/Chloroform, Rf=0.5 in 5% MeOH/CHCl₃) (1.75 g,95%).

Succinic acidmono-(4-[bis-(4-methoxy-phenyl)-phenyl-methoxymethyl]-1-{6-[17-(1,5-dimethyl-hexyl)-10,13-dimethyl2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1Hcyclopenta[a]phenanthren-3-yloxycarbonylamino]-hexanoyl}-pyrrolidin-3-yl)ester AH

Compound AG (1.0 g, 1.05 mmol) was mixed with succinic anhydride (0.150g, 1.5 mmol) and DMAP (0.073 g, 0.6 mmol) and dried in a vacuum at 40°C. overnight. The mixture was dissolved in anhydrous dichloroethane (3mL), triethylamine (0.318 g, 0.440 mL, 3.15 mmol) was added and thesolution was stirred at room temperature under argon atmosphere for 16h. It was then diluted with dichloromethane (40 mL) and washed with icecold aqueous citric acid (5 wt %, 30 mL) and water (2×20 mL). Theorganic phase was dried over anhydrous sodium sulfate and concentratedto dryness. The residue was used as such for the next step.

Cholesterol Derivatised CPG AI

Succinate AH (0.254 g, 0.242 mmol) was dissolved in a mixture ofdichloromethane/acetonitrile (3:2, 3 mL). To that solution DMAP (0.0296g, 0.242 mmol) in acetonitrile (1.25 mL),2,2′-Dithio-bis(5-nitropyridine) (0.075 g, 0.242 mmol) inacetonitrile/dichloroethane (3:1, 1.25 mL) were added successively. Tothe resulting solution triphenylphosphine (0.064 g, 0.242 mmol) inacetonitrile (0.6 ml) was added. The reaction mixture turned brightorange in color. The solution was agitated briefly using a wrist-actionshaker (5 mins). Long chain alkyl amine-CPG (LCAA-CPG) (1.5 g, 61 mM)was added. The suspension was agitated for 2 h. The CPG was filteredthrough a sintered funnel and washed with acetonitrile, dichloromethaneand ether successively. Unreacted amino groups were masked using aceticanhydride/pyridine. The achieved loading of the CPG was measured bytaking UV measurement (37 mM/g).

The synthesis of siRNAs bearing a 5′-12-dodecanoie acid bisdecylamidegroup (herein referred to as “5′-C32-”) or a 5′-cholesteryl derivativegroup (herein referred to as “5′-Chol-”) was performed as described inWO 2004/065601, except that, for the cholesteryl derivative, theoxidation step was performed using the Beaucage reagent in order tointroduce a phosphorothioate linkage at the 5′-end of the nucleic acidoligomer.

Example 2 dsRNA Expression Vectors

In another aspect of the invention, dsRNA molecules that modulate PIK4CBexpression activity or PIK4CA expression activity are expressed fromtranscription units inserted into DNA or RNA vectors (see, e.g.,Couture, A, et al., TIG. (1996), 12:5-10; Skillern, A., et al.,International PCT Publication No. WO 00/22113, Conrad, International PCTPublication No. WO 00/22114, and Conrad, U.S. Pat. No. 6,054,299). Thesetransgenes can be introduced as a linear construct, a circular plasmid,or a viral vector, which can be incorporated and inherited as atransgene integrated into the host genome. The transgene can also beconstructed to permit it to be inherited as an extrachromosomal plasmid(Gassmann, et al., Proc. Natl. Acad. Sci. USA (1995) 92:1292).

The individual strands of a dsRNA can be transcribed by promoters on twoseparate expression vectors and co-transfected into a target cell.Alternatively each individual strand of the dsRNA can be transcribed bypromoters both of which are located on the same expression plasmid. In apreferred embodiment, a dsRNA is expressed as an inverted repeat joinedby a linker polynucleotide sequence such that the dsRNA has a stem andloop structure.

The recombinant dsRNA expression vectors are generally DNA plasmids orviral vectors. dsRNA expressing viral vectors can be constructed basedon, but not limited to, adeno-associated virus (for a review, seeMuzyczka, et al., Curr. Topics Micro. Immunol. (1992) 158:97-129));adenovirus (see, for example, Berkner, et al., BioTechniques (1998)6:616), Rosenfeld et al. (1991, Science 252:431-434), and Rosenfeld etal. (1992), Cell 68:143-155)); or alphavirus as well as others known inthe art. Retroviruses have been used to introduce a variety of genesinto many different cell types, including epithelial cells, in vitroand/or in vivo (see, e.g., Eglitis, et al., Science (1985)230:1395-1398; Danos and Mulligan, Proc. Natl Acad. Sci. USA (1998)85:6460-6464; Wilson et al., 1988, Proc. Natl. Acad. Sci. USA85:3014-3018; Armentano et al., 1990, Proc. Natl. Acad. Sci. USA87:61416145; Huber et al., 1991, Proc. Natl. Acad. Sci. USA88:8039-8043; Ferry et al., 1991, Proc. Natl. Acad. Sci. USA88:8377-8381; Chowdhury et al., 1991, Science 254:1802-1805; vanBeusechem. et al., 1992, Proc. Nad. Acad. Sci. USA 89:7640-19; Kay etal., 1992, Human Gene Therapy 3:641-647; Dai et al., 1992, Proc. Natl.Acad. Sci. USA 89:10892-10895; Hwu et al., 1993, J. Immunol.150:4104-4115; U.S. Pat. No. 4,868,116; U.S. Pat. No. 4,980,286; PCTApplication WO 89/07136; PCT Application WO 89/02468; PCT Application WO89/05345; and PCT Application WO 92/07573). Recombinant retroviralvectors capable of transducing and expressing genes inserted into thegenome of a cell can be produced by transfecting the recombinantretroviral genome into suitable packaging cell lines such as PA317 andPsi-CRIP (Comette et al., 1991, Human Gene Therapy 2:5-10; Cone et al.,1984, Proc. Natl. Acad. Sci. USA 81:6349). Recombinant adenoviralvectors can be used to infect a wide variety of cells and tissues insusceptible hosts (e.g., rat, hamster, dog, and chimpanzee) (Hsu et al.,1992, J. Infectious Disease, 166:769), and also have the advantage ofnot requiring mitotically active cells for infection.

The promoter driving dsRNA expression in either a DNA plasmid or viralvector of the invention may be a eukaryotic RNA polymerase I (e.g.ribosomal RNA promoter), RNA polymerase II (e.g. CMV early promoter oractin promoter or U1 snRNA promoter) or generally RNA polymerase IIIpromoter (e.g. U6 snRNA or 7SK RNA promoter) or a prokaryotic promoter,for example the T7 promoter, provided the expression plasmid alsoencodes T7 RNA polymerase required for transcription from a T7 promoter.The promoter can also direct transgene expression to the pancreas (see,e.g. the insulin regulatory sequence for pancreas (Bucchini et al.,1986, Proc. Natl. Acad. Sci. USA 83:2511-2515)).

In addition, expression of the transgene can be precisely regulated, forexample, by using an inducible regulatory sequence and expressionsystems such as a regulatory sequence that is sensitive to certainphysiological regulators, e.g., circulating glucose levels, or hormones(Docherty et al., 1994, FASEB J. 8:20-24). Such inducible expressionsystems, suitable for the control of transgene expression in cells or inmammals include regulation by ecdysone, by estrogen, progesterone,tetracycline, chemical inducers of dimerization, andisopropyl-beta-D1-thiogalactopyranoside (EPTG). A person skilled in theart would be able to choose the appropriate regulatory/promoter sequencebased on the intended use of the dsRNA transgene.

Generally, recombinant vectors capable of expressing dsRNA molecules aredelivered as described herein, and persist in target cells.Alternatively, viral vectors can be used that provide for transientexpression of dsRNA molecules. Such vectors can be repeatedlyadministered as necessary. Once expressed, the dsRNAs bind to target RNAand modulate its function or expression. Delivery of dsRNA expressingvectors can be systemic, such as by intravenous or intramuscularadministration, by administration to target cells ex-planted from thepatient followed by reintroduction into the patient, or by any othermeans that allows for introduction into a desired target cell.

dsRNA expression DNA plasmids are typically transfected into targetcells as a complex with cationic lipid carriers (e.g. Oligofectamine) ornon-cationic lipid-based carriers (e.g. Transit-TKO™). Multiple lipidtransfections for dsRNA-mediated knockdowns targeting different regionsof the PIK4CB gene over a period of a week or more are also contemplatedby the invention. Successful introduction of the vectors of theinvention into host cells can be monitored using various known methods.For example, transient transfection. can be signaled with a reporter,such as a fluorescent marker, such as Green Fluorescent Protein (GFP).Stable transfection. of ex vivo cells can be ensured using markers thatprovide the transfected cell with resistance to specific environmentalfactors (e.g., antibiotics and drugs), such as hygromycin B resistance.

The PIK4CB and PIK4CA specific dsRNA molecules can also be inserted intovectors and used as gene therapy vectors for human patients. Genetherapy vectors can be delivered to a subject by, for example,intravenous injection, local administration (see U.S. Pat. No.5,328,470) or by stereotactic injection (see e.g., Chen et al. (1994)Proc. Natl. Acad. Sci. USA 91:3054-3057). The pharmaceutical preparationof the gene therapy vector can include the gene therapy vector in anacceptable diluent, or can comprise a slow release matrix in which thegene delivery vehicle is imbedded. Alternatively, where the completegene delivery vector can be produced intact from recombinant cells,e.g., retroviral vectors, the pharmaceutical preparation can include oneor more cells which produce the gene delivery system.

Example 3 Identification of PIK4CB and PIK4CA as Essential Host Targetsfor HCV Infection

A large scale transfection based siRNA delivery system was used toidentify the PI4KCB and PI4KCA targets. This system was describedpreviously (Borawski J, Lindeman A, Buxton F, Labow M, Gaither L A.Optimization procedure for small interfering RNA transfection in a384-well format. J Biomol Screen. 2007 June; 12(4):546-59. Epub 2007Apr. 13), incorporated herein by reference.

In the instant case, the system employed an HCV subgenomic repliconsystem designed to identify host proteins essential for HCV replication.A Huh7 subgenomic replicon cell line (as described by Lohmann, V., et.al. (1999) Science. 285:110) was screened using a kinome (i.e. the knownkinases of the human genome (Dharmacon (Boulder Colo.)) siRNA library.The HCV subgenomic replicon system allows for HCV replication to bestudied in vitro and in vivo using human hepatoma cells (Huh7) stablytransformed with the modified HCV genome lacking the structuralproteins. The HCV subgenomic replicon contains the non-structuralproteins in cis with a luciferase reporter under a neomycin selectionmarker. This construct was designed for stable in vitro measurement ofthe HCV replicon RNA levels and replicon activity. The goal of thisstudy was to use siRNA screening technology as a tool to identify novelhost proteins that inhibit the subgenomic HCV replicon in Huh7 cells.

To this end, a set of 779 siRNA smart pools targeting the kinome wasscreened and novel regulators of the HCV replicon were discovered andverfied. (Smart pool referres to mixing 4 individual siRNAs inequalmolar concentrations before adding the mixture to cells.) siRNAs toPIK4CB (phosphatidylinositol 4-kinase, catalytic, beta polypeptide) orPIK4CA ((phosphatidylinositol 4-kinase, catalytic, alpha polypeptide),were identified that inhibited accumulation of luciferase from the viralreplicon with high potency. These data establish that this cellularprotein can be used as a drug target for the inhibition of HCVreplication.

Construction of the Huh7 subgenomic replicon cell line (also calledherein Clone A cells) is based on the HCV genome. The full length HCVgenome is illustrated in FIG. 1A. The 9.6 kb genome is a positive singlestranded RNA virus with four structural and six non-structural proteins.A salient feature of the replicon is the 5′ and 3′ UTRs which arerequired for efficient replicon activity. This virus can replicate invitro but creates infectious virus, requiring special training andfacilities (Thomson B J, Finch R G. Hepatitis C virus infection. ClinMicrobiol Infect. 2005 February; 11(2):86-94.). Therefore the infectiousvirus was altered to create a minimal viral genome capable ofreplication in vitro without the liability of creating infectiousparticles. The construct is shown in FIG. 1B, the HCV subgenomicreplicon which used to create the Clone A cells (Lohmann V, Korner F,Koch J, Herian U, Theilmann L, Bartenschlager R. Replication ofsubgenomic hepatitis C virus RNAs in a hepatoma cell line. Science. 1999Jul. 2; 285(5424):110-3). This virus was highly optimized to capture HCVreplicon activity in vitro, in human liver cells. It cannot createinfectious viral particles but can self-replicate in the cytoplasm,making it amenable for cell culture studies as well as high throughputscreening. The structural proteins have been replaced with a neomycinresistance gene and a firefly luciferase reporter to measure repliconactivity. The Clone Ar construct is made up of the same back-bone as thesubgenomic virus but the structural proteins have been removed (FIG.1C). This cell line was used to test if siRNAs could non-specificallyinhibit luciferase activity or expression.

siRNA smart pools directed to 779 phylogenetically related kinases weretransfected into the Clone A (HCV subgenomic replicon) cells. A siRNAduplex directed against pGL2 luciferase was used as a positive controlto inhibit luciferase activity. Cells were transfected for 72 hours andluciferase activity was measured using the Bright-Glo luciferase assay(Borawski J, Lindeman A, Buxton F, Labow M, Gaither L A. Optimizationprocedure for small interfering RNA transfection in a 384-well format. JBiomol Screen. 2007 June; 12(4):546-59. Epub 2007 Apr. 13).

Several siRNAs were found to be potent inhibitors of luciferaseactivity, including those pools targeting PIK4CB (NM_(—)002651) andPIK4CA (NM_(—)002650).

Example 4 Confirmation and Measurement of PIK4CB and PIK4CA siRNAActivity

Confirmation of siRNA hits from a screen was achieved with a series ofsteps including analysis of multiple independent gene specific siRNAs aswell as correlating phenotypically active siRNAs with efficiency of mRNAknock down. To first confirm the specificity of the siRNA hits, multiplesequence independent siRNAs were tested both for the ability to inhibitluciferase activity and inability to affect cell viability. The siRNAhits were also tested in the Clone Ar (similar to Clone A but lackingstructural proteins as in FIG. 1 c) cells to confirm that the siRNAswere specifically targeting the replicon proteins and not inhibitingluciferase activity (or expression) in a replicon independent manner.

The next step was phenotype and RTPCR validation. Four independentsiRNAs for PIK4CB and four independent siRNAs for PIK4CA were analyzedfor their ability to knock down replicon activity, effects on cellviability, and ability to knock down target gene mRNA levels.

The siRNA employed in this example were as set out in Table 1 and Table2.

FIG. 2 demonstrates results of dsRNA targeting PIK4CB and PIK4CA in theClone A assay. Results of testing dsRNA as individual duplexesPIK4CA1-PIK4CA4 (column 1-4) as a PIK4CA Smart Pool (col. 5), asindividual duplexes PIK4CB1-PIK4CB4 (col. 6-9) or as a PIK4CB Smart Pool(Col. 10). Cells were transfected for 72 hours and luciferase activitywas measured using the Bright-Glo luciferase assay (Borawski J, LindemanA, Buxton F, Labow M, Gaither L A. Optimization procedure for smallinterfering RNA transfection in a 384-well format. J Biomol Screen. 2007June; 12(4):546-59. Epub 2007 Apr. 13). Results are measured relative toGAPDH (control; column 11), Assay performed using 25 nM of dsRNA perwell using Clone A cells; Bright-Glo activity measured at 72 hours posttransfection. dsRNA targeting GAPDH (column 11) was used as the negativecontrol and dsRNA targeting pGL2 (column 12) was the positive control.

Results in FIG. 2 show that relative to GAPDH, dsRNA directed to PIK4CBor PIK4CA can reduce the expression of the HCV replicon (measured byluciferase expression) in the Clone A cells by at least 20% and up toabout 90%. A variety of intermediate acitivites are identified.Additional data confirms that the dsRNA of this assay do not hinder cellviability nor do they demonstrate significant non-specific effects onthe cells in the Clone Ar assay (data not shown).

FIGS. 3A and 3B confirm that the PIK4CA targeted dsRNA are specific forPIK4CA and not PIK4CB; FIGS. 3C and 3D confirm that PIK4CB targeteddsRNA are specific for PIK4CB and not PIK4CA.

Results for FIG. 3 were generated using Real-Time PCR In this method,two wells transfected with siRNAs were pooled together and mRNA wasisolated using the RNeasy96 kit (Qiagen #74182). Preparations were DNAse1 treated twice for 15 minutes each. cDNA was generated using the HighCapacity cDNA Archive kit (Applied Biosystems #4322171), and the RNA wasprimed using Oligo dT25 (Sigma Genosys). PCR buffer (Roche #1699105) wassupplemented with MgC12 (Ambion #9530g) as follows; 10× buffer at 10 μl,1M MgCl2 at 0.55 μl, 50 uM oligo dT25, 100 mM dNTPs at 4 μl, RNasIn, 20U/μl at 4 μl, Multiscribe 50 U/μl at 5 μl, water at 12.45 μl, and RNA at66 μl for a total volume of 100 μl. The cDNA was quantified usingprimers designed in house, PIK4CA (NM_(—)002650)

Fwd: GCCCTGTCTGAAGTGAAGGT, SEQ ID No.: 417 Reverse:CTTTTGCAGCACTCTGCATC, SEQ ID No.: 418

At 1662: crossing intron 3006 bp at 1690 At 1774 reversed: crossingintron 3006 bp at 1690;

PIK4CB was measured using primers designed in house against PIK4CB(NM_(—)002651)

Fwd: ATGGACAAGGTGGTGCAGAT SEQ ID No.: 419 Reverse: CCTCAGTCATGCTCATGTGGSEQ ID No.: 420

At 2334 to 2452: crossing intron 981 bp at 2374; (Sigma Genosys) usingSyber green on an Applied Biosystems 7900HT (Applied Biosystems#4329001). In FIG. 3, the label “sp” refers to the term SMARTpool. Itreferres to mixing 4 individual siRNAs in equalmolar concentrationsbefore adding the mixture to cells. In a Smart Pool, 4 individual siRNAsare added at lower relative concentrations (i.e.—a 50 nM equalmolarconcentration would be 12.5 nM concentration for each individual siRNAin the SMART pool).

Further confirmation of the targets was achieved using another set ofthree individual duplexes against PIK4CA (NM_(—)002650, Dharmacon#D-006776) and PIK4CB (NM_(—)002651, Dharmacon #D-006777). siRNAemployed as indicated in Table 1 and Table 2.

Each siRNA was resuspended in siRNA buffer (Dharmacon, #B-002000-UB-015)to a stock concentration of 20 μM. 2.5 μL of each stock solution wasdiluted in 197.5 μL Opti-Mem in a 96 well PCR plate (ABgene, #AB-1000)to make a 250 nM working stamp. 0.20 μL of Dharmafect1 transfectionreagent (Dharmacon, #T2001-03) diluted in 10 μL Opti-Mem was added toeach well of a 96 well tissue culture plate (Costar, #3917). 10 μL ofeach siRNA stamp was added to the 96 well plate containing theDharmafect 1 and incubated for 20 minutes to allow complexes to form.After the incubation, 6000 Huh7 HCV subgenomic replicon cells in 80 μLassay media were added per well. Cells were incubated for 72 hours andassayed for luciferase activity and cell viability (as describedpreviously for FIG. 2).

In FIG. 4 each of the siRNAs was validated using the Taqman GeneExpression Assay (Applied Biosystems) per manufacturer's instructions.siRNAs were transfected in Huh7 HCV subgenomic replicon cells in 96 wellformat as described above. mRNA was isolated using the RNeasy96 Kit(Qiagen, #74182). mRNA from duplicate wells were pooled together andcDNA was generated using the Sprint Powerscript Preprimed 96 Plate Oligo(dt) (Clontech Laboratories, #639557). The cDNA was quantified usingpremixed Taqman probes and primers from Applied Biosystems, PIK4CA(NM_(—)002650, Applied Biosystems #Hs01021073_ml) PIK4CB (NM_(—)002651,Applied Biosystems #Hs00356327_m1) in 384 well format. 4.8 μL cDNA perwell was added to a 384 well PCR plate (Applied Biosystems, #4309849).0.6 μL of the Taqman probe for the gene of interest (GOD, 0.6 μL β-Actincontrol probe (Applied Biosystems, #4310881E) and 6 μL 2×PCR Master Mix(Applied Biosystems, #4304437) was added to the cDNA per well. Thereaction was run on an Applied Biosystems 7900HT Real Time PCR system(Applied Biosystems, #4329001).

In FIG. 4A cells were transfected with PI4KA siRNAs and mRNA wasmeasured using both PI4KA and PI4KB RTPCR Taq man probes. In FIG. 4Bcells were transfected with PI4KB siRNAs and mRNA was measured usingboth PI4KA and PI4KB RTPCR Taq man probes. As demonstrated by the figurethe siRNAs specifically knock-down their designated targets and do notcross react and inhibit the other PI4K mRNA transcript or the control(GAPDH).

Example 5 Inhibition of Host and Viral Protein Expression

In FIG. 5 whole cell lysates were made from Huh7 HCV subgenomic repliconcells transfected with siRNA or naïve cells alone. siRNA employed forthe results in FIG. 5 are as named in Table 1 and Table 2.

Cells were lysed in radioimmunoprecipitation buffer (RIPA) (BostonBioproducts, #BP-115) containing one protease cocktail inhibitor tablet(Roche, #04693116001) per 10 ml lysis buffer. Lysates were quantifiedusing the BCA Protein Assay (Pierce Biotechnology, #23227) per themanufacturer's instructions. Equal amounts of lysate were loaded on a15% Tris-HCL gel (Bio-Rad Laboratories, Hercules, Calif., #345-0019) andrun at 200V for 1 hour. The gel was transferred to a nitrocellulosemembrane (Bio-Rad Laboratories, #162-0232) for 1 hour at 100V. Themembrane was blocked in 5% milk (Bio-Rad Laboratories, Hercules, Calif.,#162-0232), TBS-0.1% Tween (Bio-Rad Laboratories, #170-6435, #161-0787),for 1 hour. Blots were probed with a mouse monoclonal antibody againstPIK4CB (BD Biosciences, #611817) or a mouse monoclonal against the HCVprotein NS3 (Virostat, #1828) and a mouse monoclonal antibody for13-Actin (Sigma, St. Louis, Mo., #A-5441), as a loading control, dilutedin blocking buffer 1:1000 for 1 hour (antibodies against PIK4CA were notavailable). Following three successive washes with TBS-0.1% Tween(TBST), HRP-conjugated secondary antibody for mouse IgG (Sigma, #A4416),diluted in blocking buffer 1:5000, was added for 1 hour. The membranewas washed three times in TBST and immunoreactive bands were visualizedusing the SuperSignal West Femto chemiluminescent substrate (Pierce,#34096). There was no PI4KA antibody available so only the PI4KB proteinwas detected in FIG. 5.

Results in FIG. 5 show that the PI4KA siRNAs had no effect on PI4KBprotein levels while the PI4KB siRNAs ablate the PI4KB protein in theHuh7 cells. Each siRNA tested also showed a measurable reduction in NS3(viral) protein production relative to control, thus confirming directactivity on viral replication ability. The reduction of mRNA levelsusing these siRNAs correlated with protein knock down suggesting thesehuman proteins are required for HCV replication.

Example 6 Confirmation Using Short Hairpin RNA (shRNA)

In FIG. 6 Short hairpin RNAs (shRNAs) targeting PIK4CA (NM_(—)002650)and PIK4CB (NM_(—)002651), were ordered as 5 individual Sigma MISSION™shRNA. shRNAs targeting CD3δ (NM_(—)000732), CD28 (NM_(—)006139), CD29(NM_(—)033666) and GFP (U76561) were used as negative controls forinhibiting HCV replication (only GFP data shown). All shRNA sequenceswere constructed as in the human library MISSION™ TRC-Hs 1.0. (Human)(Moffat J. et al., A Lentiviral RNAi Library for Human and Mouse GenesApplied to an Arrayed Viral High-Content Screen. Cell, 124, 1283-1298.2006.; Stewart, S. A., et al., Lentivirus-delivered stable genesilencing by RNAi in primary cells., RNA, 9, 493-501 (2003); Zufferey R,et al., Multiply attenuated lentiviral vector achieves efficient genedelivery in vivo., Nat. Biotechnol. 15, 871-85 (1997).; Zufferey R, etal., Self-inactivating lentivirus vector for safe and efficient in vivogene delivery., J. Virol., 72, 9873-80 (1998).

The shRNA sequences were distinct independent sequences from the siRNAsreported in the aforementioned experiments. Table 4 sets out the DNAsequences corresponding to the expressed RNA strand.

TABLE 4 SEQ shRNA Sequence (5′ to 3′) ID No. ShA-1CCGGGCTGCACAAATACTACATGAACTCGAGTTCATGTAGTATTTGTGCAGCTTTTT 421 ShA-2CCGCGCGTCTCATCACATGGTACAACTCGAGTTGTACCATGTGATGAGACGCTTTTT 422 ShA-3CCGGGCCAGGTTTAAGAACACAGAACTCGAGTTCTGTGTTCTTAAACCTGGCTTTTT 423 ShA-4CCGGCCAGTTCATCTGGAACATGAACTCGAGTTCATGTTCCAGATGAACTGGTTTTT 424 ShA-5CCGGCAAGCTCTTGAAGCACAGGTTCTCGAGAACCTGTGCTTCAAGAGCTTGTTTTT 425 ShB-1CCGGCCAGTTGCTTAACATGTACATCTCGAGATGTACATGTTAAGCAACTGGTTTTT 426 ShB-2CCGGCCGACAGTATTGATAATTCATCTCGAGATGAATTATCAATACTCTGGGTTTTT 427 ShB-3CCGGCCATACAAGATTCTTGTGATTCTCGAGAATCACAAGAATCTTGTATGGTTTTT 428 ShB-4CCGGCGACATGTTCAACTACTATAACTCGAGTTATAGTAGTTGAACATGTCGTTTTT 429 ShB-5CCGGTCTCGGTACTTAGGACTTGATCTCGAGATCAAGTCCTAAGTACCGAGATTTTT 430

To test the shRNA, 6000 Huh7 HCV subgenomic replicon cells were platedin 96 well tissue culture plates. The following day, media was replacedwith transduction media containing assay media with polybrene (sigmaH9268) 8 ug/ml final concentration and hepes (Invitrogen, #15630080) 10mM final concentration. 1 μL shRNA virus was added per well and cellswere centrifuged at 2100 rpms for 90 minutes at room temperature. Cellswere incubated for 24 hours and were selected by adding puromycin(Sigma, #P9620) at 2 μg/ml final concentration. Cells were thenincubated for a minimum of 72 hours and assayed for phenotype, analyzedby western and RT-PCR or propagated for long term knockdown studies. InFIG. 6A HCV replicon expression is measured by luciferase activity andnormalized to GAPDH shRNA transduced cells. PI4KA and PI4KB mRNA levelswere measured in the Huh7 cells after shRNA transduction using a PI4KATaqman probe (FIG. 6B) or PI4KB Taqman probe (FIG. 6C) for RTPCR. PI4KBprotein and NS3 protein levels were determined using Western blotmethods similar to those in Example 5. Protein levels were measuredafter shRNA transduction for 96 hours (FIG. 6D) and for 3 weeks (FIG.6E).

Results in FIG. 6A show that shRNA directed to PI4KA or PI4KB shRNAs canreduce HCV replicon activity as measured by luciferase activity andnormalized to GAPDH shRNA transduced cells. FIG. 6B shows relativelevels of PI4KA mRNA after treatment. The shRNA directed to PI4KAdemonstrate substantial knock-down, whereas only one of those targetingPI4KB had an effect on PI4KA levels (perhaps due to high copy number anda low cross-reactivity with PI4KA). FIG. 6C shows that the shRNAdirected to PI4KA had no effect on PI4KB mRNA levels, whereas most ofthe shRNA targeting PI4KB had significant knock-down of PI4KB. FIG. 6Dshows at 96 hours after treatment, shRNA directed to either PI4KA orPI4KB successfully lowers NS3 viral protein production (and that PI4KAshRNA does not down regulate PI4KB protein levels). The results in FIG.6E demonstrate that the knock-down of viral protein production canpersist for at least 3 weeks In conclusion, there was a clearcorrelation between PI4KA mRNA reduction and NS3 protein levelsindicating viral load in the cell was inhibited. There was a clearcorrelation between PI4KB mRNA and protein reduction and NS3 proteinlevels indicating viral load in the cell was inhibited.

Example 7 Treatment Before Infection or after Infection with Live Virus

In this example, effective inhibition of HCV replication is achieved bytreating cells before HCV infection with siRNA against either PIK4CA orPIK4CB (FIG. 7) or treating cells after HCV infection (FIG. 8). Thisexample also demonstrates dose dependence of mRNA knock-down.

For this experiment, siRNAs against PIK4CA and PIK4CB (as designated inTable 1 and Table 2) were resuspended in siRNA buffer (Dharmacon,#B-002000-UB-015) to a stock concentration of 20 μM. 3 μL of each stocksolution was diluted in 197 μL Opti-Mem in a 96 well PCR plate (ABgene,#AB-1000) to make a 300 nM working stamp. siRNAs were diluted in Optimem(Invitrogen Cat #51985-034) as 10× stocks and added to complete cellculture media to a final concentration of 25 nM, 1.5 nM, and 0.1 nM.0.20 μL of Dharmafect1 transfection reagent (Dharmacon, #T2001-03)diluted in 10 μL Opti-Mem was added to each well of a 96 well tissueculture plate (Costar, #3917). 10 μL of each siRNA stamp was added tothe 96 well plate containing the Dharmafect1 and incubated for 20minutes to allow complexes to form. After the incubation, 10000 Huh7.5cells in 100 μL assay media were added per well. Cells were incubatedfor 24 hours and then infected with the JFH-1 infectious HCV genotype 2virus which contains a Renilla reporter. A siRNA against Renilla wasused as positive control for inhibiting the Renilla, luciferase. ThesiRNAs were transfected before live virus infection (FIG. 7A) or afterviral infection (FIG. 8A) demonstrating the siRNAs could block bothuptake and replication of the HCV virus. Viral supernatants werecollected over a time course to measure live virus secreted from thecells as measured by percent reinfection of naïve cells (FIG. 8B). Thepercent knock down of the mRNA in the Huh7 cells was determined by RTPCR(FIG. 7B).

We have used an Huh7 HCV replicon siRNA screen that identified severalnovel host factors required for optimal replicon driven luciferaseactivity. This screen was used to confirm the findings. This screen doesnot directly measure viral replication, it is assumed that luciferaseexpression levels are directly determined by the copy number of thevirus replicon. The experiments illustrated in FIG. 7 and FIG. 8indicate that active siRNAs described here indeed result in reduction ofviral RNA production.

From a smart pool kinome screen, PIK4CB and PIK4CA have been identifiedas an essential host factors for HCV and other positive stranded RNAvirus replication. Multiple independent siRNAs targeting the gene couldsignificantally reduce luciferase levels while having no effect oncellular viability in the replicon cells. The siRNAs that reducedluciferase levels also inhibited mRNA levels of the respective targetgenes. Thus, we can conclude the siRNAs used in this study are on-targetand significantly modulate HCV replication via reduction of their targetcellular genes.

Without wishing to be bound to any particular mechanism of action toexplain our findings, it is clear that the significance of thesefindings are several fold. PIK4 enzymes are required for the productionof PtdIns4P in the ER and Golgi compartments. The production of PtdIns4Pis needed to maintain Golgi integrity, bud vesicles from the Golgi andER membranes, and modulate the production of Ins(1,4,5)P₃, an essentialsignalling molecule through the intermediate Ins(4,5)P₂ (Godi A, PertileP, Meyers R, Marra P, Di Tullio G, Iurisci C, Luini A, Corda D, DeMatteis M A. ARF mediates recruitment of PtdIns-4-OH kinase-beta andstimulates synthesis of PtdIns(4,5)P2 on the Golgi complex. Nat CellBiol. 1999 September; 1(5):280-7.) While not desiring to be bound to anyspecific mechanism of action for the discovery herein, it is possiblethe activity of PIK4 enzymes could be linked to HCV replication based onthe location of the HCV replication complex. If the replication complexrequires intact Golgi and ER membranes then the disruption of PIK4enzymes, and PtdIns4P production, would likely block the formation of acompetent replication environment. As well, PIK4 enzymes are known toregulate trafficking of cerimide and cholesterol through the Golgi andER membranes and aid in the formation of lipid rafts (Toth B, Balla A,Ma H, Knight Z A, Shokat K M, Balla T. Phosphatidylinositol 4-kinaseIIIbeta regulates the transport of ceramide between the endoplasmicreticulum and Golgi. J Biol Chem. 2006 Nov. 24; 281(47):36369-77.) It isa strong possibility that the HCV replication complex requires lipidrafts for effective activity. If PIK4 knock down also perturbscholesterol and cerimide transport, it could also contribute toinhibition of HCV replication (Ridsdale A, Denis M, Gougeon P Y, Ngsee JK, Presley J F, Zha X. Cholesterol is required for efficient endoplasmicreticulum-to-Golgi transport of secretory membrane proteins. Mol BiolCell. 2006 April; 17(4):1593-605.) Finally, a number of proteins havebeen identified that contain PIP(4,5) specific PH domains andlocalization of such proteins appear to be regulated by PIK4 enzymes.Thus the role of PIK4 may also include redirecting cellular or viralproteins to sites of replication.

In conclusion, we have identified that PIK4CB and PIK4CA are human hostfactor enzymes that are required for HCV replication, and that dsRNAtargeting these genes are suitable therapeutic targets for treating HCVand other positive stranded virus infections.

Those skilled in the art are familiar with methods and compositions inaddition to those specifically set out in the instant disclosure whichwill allow them to practice this invention to the full scope of theclaims hereinafter appended.

1.-63. (canceled)
 64. A double-stranded ribonucleic acid (dsRNA) forinhibiting the expression of phosphatidylinositol 4-kinase (PI4K) in acell, wherein said dsRNA comprises a first strand and a second strand,wherein the sequence of the first strand comprises the sequence of SEQID NO:
 1. 65. The dsRNA of claim 64, wherein the sequence of the secondstrand comprises the sequence of SEQ ID NO:
 105. 66. The dsRNA of claim64, wherein said dsRNA comprises at least one modified nucleotide. 67.The dsRNA of claim 66, wherein said modified nucleotide is chosen fromthe group of: a 2′-O-methyl modified nucleotide, a nucleotide comprisinga 5′-phosphorothioate group, and a terminal nucleotide linked to acholesteryl derivative or dodecanoic acid bisdecylamide group.
 68. ThedsRNA of claim 66, wherein said modified nucleotide is chosen from thegroup of: a 2′-deoxy-2′-fluoro modified nucleotide, a 2′-deoxy-modifiednucleotide, a locked nucleotide, an abasic nucleotide, 2′-amino-modifiednucleotide, 2′-alkyl-modified nucleotide, morpholino nucleotide, aphosphoramidate, and a non-natural base comprising nucleotide.
 69. Apharmaceutical composition comprising the dsRNA of claim 64 and apharmaceutically acceptable carrier.
 70. A composition comprising thedsRNA of claim 64, further comprising one or more additional dsRNAs forinhibiting the expression of phosphatidylinositol 4-kinase (PI4K) in acell.
 71. A method for inhibiting the expression of thephosphatidylinositol 4-kinase, catalytic, beta polypeptide (PIK4CB) genein a cell, the method comprising the steps of: (a) introducing into thecell a double-stranded ribonucleic acid (dsRNA) for inhibiting theexpression of phosphatidylinositol 4-kinase (PI4K) in a cell, whereinsaid dsRNA comprises a first strand and a second strand, wherein thesequence of the first strand comprises the sequence of SEQ ID NO: 1; and(b) maintaining the cell produced in step (a) for a time sufficient toobtain degradation of the mRNA transcript of the PIK4CB gene, therebyinhibiting expression of the PIK4CB gene in the cell.
 72. The method ofclaim 71, wherein the sequence of the second strand comprises thesequence of SEQ ID NO:
 105. 73. The method of claim 71, wherein saiddsRNA comprises at least one modified nucleotide.
 74. The method ofclaim 71, wherein said modified nucleotide is chosen from the group of:a 2′-O-methyl modified nucleotide, a nucleotide comprising a5′-phosphorothioate group, and a terminal nucleotide linked to acholesteryl derivative or dodecanoic acid bisdecylamide group.
 75. Themethod of claim 71, wherein said modified nucleotide is chosen from thegroup of: a 2′-deoxy-2′-fluoro modified nucleotide, a 2′-deoxy-modifiednucleotide, a locked nucleotide, an abasic nucleotide, 2′-amino-modifiednucleotide, 2′-alkyl-modified nucleotide, morpholino nucleotide, aphosphoramidate, and a non-natural base comprising nucleotide.
 76. Amethod of treating a pathological process mediated by positive strandedRNA virus infection comprising the step of administering to a patient inneed of such treatment, prevention or management a therapeutically orprophylactically effective amount of a double-stranded ribonucleic acid(dsRNA) for inhibiting the expression of phosphatidylinositol 4-kinase(PI4K) in a cell, wherein said dsRNA comprises a first strand and asecond strand, wherein the sequence of the first strand comprises thesequence of SEQ ID NO:
 1. 77. The method of claim 76, wherein saidpositive stranded RNA virus is selected from among hepatitis C virus(HCV), human papilloma virus (HPV), and Dengue virus.
 78. The method ofclaim 76, wherein the sequence of the second strand comprises thesequence of SEQ ID NO:
 105. 79. The method of claim 76, wherein saiddsRNA comprises at least one modified nucleotide.
 80. The method ofclaim 76, wherein said modified nucleotide is chosen from the group of:a 2′-O-methyl modified nucleotide, a nucleotide comprising a5′-phosphorothioate group, and a terminal nucleotide linked to acholesteryl derivative or dodecanoic acid bisdecylamide group.
 81. Themethod of claim 76, wherein said modified nucleotide is chosen from thegroup of: a 2′-deoxy-2′-fluoro modified nucleotide, a 2′-deoxy-modifiednucleotide, a locked nucleotide, an abasic nucleotide, 2′-amino-modifiednucleotide, 2′-alkyl-modified nucleotide, morpholino nucleotide, aphosphoramidate, and a non-natural base comprising nucleotide.
 82. Avector for inhibiting the expression of the phosphatidylinositol4-kinase, catalytic, beta polypeptide (PIK4CB) gene in a cell, saidvector comprising a regulatory sequence operably linked to a nucleotidesequence that encodes at least one strand of the dsRNA of claim
 64. 83.A cell comprising the vector of claim 74.